MT90840
Distributed Hyperchannel Switch
Data Sheet
Features
•
June 2007
Time slot interchange function between eight
pairs of ST-BUS/GCI/MVIP streams (512
channels) and parallel data port
Ordering Information
MT90840AL1
MT90840AP1
MT90840APR1
•
Programmable data rates on the parallel port
(19.44, 16.384, or 6.480 Mbyte/s)
•
Programmable data rates on the serial port (2.048
Mbps, 4.096 Mbps or 8.192 Mbps)
•
Supports star and point-to-point connections, and
unidirectional or bidirectional ring topologies for
distributed systems
100 Pin MQFP*
84 Pin PLCC*
84 Pin PLCC*
Trays
Tubes
Tape & Reel
*Pb Free Matte Tin
•
Input-to-output bypass function on the parallel
data port for use in add/drop applications
•
Provides elastic buffer at parallel input port in the
receive direction
•
Provides byte switching for up to 2430 channels
•
-40°C to +85°C
•
Guarantees frame integrity when switching nX64
wideband channels such as ISDN H0 channel
•
Provides external control lines allowing fast
parallel interface to be shared with other devices
Applications
•
Bridging ST-BUS/MVIP buses to high speed Time
Division Multiplexed backplanes at SONET rates
(STS-1, STS-3)
Per-channel direction control on the serial port
side
•
High speed isochronous backbones for distributed
PBX and LAN systems
•
Per-channel message mode and high-impedance
control on both parallel and serial port sides
•
Switch platforms of up to 2430 channels with
guaranteed frame integrity for wideband channels
•
8-bit multiplexed microprocessor port compatible
with Intel and Motorola microcontrollers
•
Serial bus control and monitoring
•
Data multiplexing
•
High speed communications interface
Output
Mux &
Drivers
PDo7
2430 Position
TX Path
Connection Memory
8
Parallel
to
Serial
PDi0
8
Multiple Pages of 2430-Byte
RX Path Data Memory
8
PDi7
Converters
15
512 Position
RX Path
Connection Memory
Timing
Bidirectional
I/O
Driver
STi0
Bidirectional
I/O
Driver
STo0
Unit
Internal
Registers
CPU Interface
8
VSS
VDD
DTA
CS
AS/ALE
R/W\WR
DS/RD
AD0-7
IRQ
C4/8R2
8
C4/8R1
STi7
STo7
5
JTAG
Control
SPCKo
PCKR
PCKT
RES
PPFRi
PPFTi/o
F0i/o
Serial
to
Parallel
&
16
4
CTo0-3
8
Multiple Pages of 512 Position
TX Path Data Memory
8
PDo0
Figure 1 - Functional Block Diagram
1
Zarlink Semiconductor Inc.
Zarlink, ZL and the Zarlink Semiconductor logo are trademarks of Zarlink Semiconductor Inc.
Copyright 2002-2007, Zarlink Semiconductor Inc. All Rights Reserved.
TEST
Pins
MT90840
Data Sheet
Change Summary
Changes from April 2006 to April 2007. Page, section, figure and table numbers refer to this current issue.
Page
Item
Change
1
Ordering Information Box
Removed part numbers MT90840AL and MT90840AP from
ordering information.
2
Zarlink Semiconductor Inc.
MT90840
74
14
72
16
70
18
68
20
66
84 PIN PLCC
22
64
24
62
26
60
28
58
30
52
50
48
46
44
42
40
38
54
NC
NC
NC
NC
VDD
NC
PDo7
VDD
PDo6
VSS
PDo5
CTo0
PDo4
CTo1
PDo3
CTo2
PDo2
CTo3
PDo1
VDD
PDo0
VSS
C4/8R2 PPFTi/o
VSS
F0i/o
VDD
C4/8R1
PDi7
STi7
PDi6
STi6
PDi5
STi5
STi4
PDi4
STi3
PDi3
STi2
PDi2
STi1
PDi1
STi0
PDi0
VDD
VSS
VSS
NC
NC
NC
NC
36
56
34
32
VSS
VSS
STo0
STo1
STo2
STo3
STo4
STo5
STo6
STo7
SPCKo
VSS
VDD
TDO
TMS
TCK
TRST
TDI
PPFRi
PCKT
PCKR
VDD
76
78
80
82
84
2
4
6
12
8
VDD
STi0
STi1
STi2
STi3
STi4
STi5
STi6
STi7
C4/8R1
F0i/o
C4/8R2
VSS
VDD
NC
NC
CTo3
CTo2
CTo1
CTo0
10
VSS
NC
IC
RES
IRQ
DTA
CS
AS/ALE
DS/RD
VDD
VSS
R/W
AD7
AD6
AD5
AD4
AD3
AD2
AD1
AD0
VDD
Data Sheet
80
78
76
74
72
70
68
66
64
62
60
58
56
54
82
52 50
48
84
46
86
44
88
42
90
40
100 PIN PQFP
92
38
94
36
96
34
98
100 2
4
6
8
10
12
14
16
18
20
22
24
26
28
32
30
NC
NC
NC
NC
VDD
PCKR
PCKT
PPFRi
TDI
TRST
TCK
TMS
TDO
VDD
VSS
SPCKo
STo7
STo6
STo5
STo4
STo3
STo2
STo1
STo0
VSS
VDD
NC
NC
NC
NC
PDo7
PDo6
PDo5
PDo4
PDo3
PDo2
PDo1
PDo0
PPFTi/o
VSS
VDD
PDi7
PDi6
PDi5
PDi4
PDi3
PDi2
PDi1
PDi0
VSS
Figure 2 - Pin Connections
3
Zarlink Semiconductor Inc.
NC
IC
RES
IRQ
DTA
CS
AS/ALE
DS/RD
VDD
VSS
R/W
AD7
AD6
AD5
AD4
AD3
AD2
AD1
AD0
NC
MT90840
Data Sheet
Pin Description
Pin #
Name
Description
84
100
3
43
DS/RD
Data Strobe/Read (Input). In Motorola multiplexed-bus mode this pin is DS, an
active high input which works with CS to enable read and write operation. In
Intel/National multiplexed-bus mode this pin is RD, an active low input which
enables a read-cycle and configures the data bus lines (AD0-AD7) as outputs.
4
44
AS/ALE
Address Strobe / Address Latch Enable (Input). Falling edge is used to sample
address into the Address Latch circuit.
5
45
CS
Chip Select (Input). Active low input enabling a microprocessor read or write of
control or status registers.
6
46
DTA
Data Acknowledgment (Active Low Output). Indicates that a data bus transfer is
complete. When the bus cycle ends, this pin drives HIGH and then tri-states,
allowing for faster bus cycles with a weaker pull-up resistor. A pull-up resistor is
required to hold a HIGH level when the pin is tri-stated. Note that CPU read/writes
from/to the Data and Connection memories occur on the serial or parallel port
clock edges, and DTA will not change state if the clock is halted.
7
47
IRQ
Interrupt Request (Active High Output). Output indicates that the MT90840 has
detected an alarm condition. The indication of the specific condition can be read in
the ALS (Alarm Status) Register. The CPU should read ALS, identify the source for
the interrupt and then rewrite the mask bits to re-enable the IRQ signal.
8
48
RES
RESET (Schmitt Input). Asynchronous device reset. A logic-high signal should be
applied during power-up to bring the MT90840 internal circuitry to a defined state.
Serial and parallel TDM outputs (STo0-7, STi0-7, and PDo0-7) are held in highimpedance state after reset until programmed otherwise. This input must be held
low during normal operation.
9
49
IC
Internal Connection. The user must connect this pin to VSS. This pin must remain
low for the MT90840 to function normally, and to comply with IEEE 1149 (JTAG)
boundary scan requirements. This pin is pulled low internally when not driven.
10,
26,
27
1-4,
27-31
50-54
76-80
NC
No Connection.
13-20
57-64
STi0-STi7
Serial Inputs 0 to 7 (Bidirectional). Serial TDM data-streams at 2.048, 4.096 or
8.192 Mbps, with 32, 64 or 128 channels respectively per stream. For 2.048 and
4.096 Mbps applications, streams STi0-STi7 can be used, while for 8.192 Mbps,
only streams STi0-STi3 are used (512 channel limit). These eight bidirectional
lines can be programmed as inputs (default) or outputs on a per-channel basis.
4
Zarlink Semiconductor Inc.
MT90840
Data Sheet
Pin Description (continued)
Pin #
84
100
21
65
Name
Description
C4/8R1
Serial Clock Reference Input 1. When enabled by the C4/8R bit (high) in the TIM
Register, this input receives the 4.096 or 8.192 MHz serial port clock reference. If
the C4/8R bit is set low, or if the INTCLK bit is set high, this input is ignored by the
MT90840.
In Timing Mode 1 (TM1), or at 8.192 MHz, the C4/8 input is used directly to shift
data in and out of the serial port.
In Timing Mode 2 (TM2) at 4.096 MHz, the C4 input from an external clock source
(e.g. a PLL locked to an 8 kHz reference) is phase-corrected by the MT90840, and
used to generate the serial port SPCKo and F0 outputs.
In Timing Modes 3 and 4 (TM3 and TM4) this input is not used.
For more details on the use of this signal, see the description of Timing Mode 1
and Timing Mode 2.
22
66
F0i/o
Serial Port Frame Synchronization (Bidirectional). This 8 kHz frame pulse signal
indicates the TDM 125 µsec frame boundary on the serial data port. This pin is
compatible with both ST-BUS/MVIP and GCI formatted framing signals.
In TM1 this pin is an input, and the MT90840 senses the polarity of this frame
pulse and automatically adapts the serial data port timing to the applicable format
(ST-BUS or GCI).
In TM2 with SFDI =1 this signal is an input, and its expected format is determined
by the SPFP bit in the GPM Register.
In TM2 (with SFDI =0), and in TM3, this signal is an output, generated from the
internal timing and synchronized to the SPCKo output clock. The polarity of the F0
pulse is determined by the SPFP bit in the GPM Register.
In TM4 this pin is not used.
23
67
C4/8R2
C4/8R2 Serial Clock Reference Input 2. When enabled by the C4/8R bit (low) in
the TIM Register, this input receives the 4.096 or 8.192 MHz serial port clock
reference. If the C4/8R bit is set high, or if the INTCLK bit is set high, this input is
ignored by the MT90840. (See pin description for C4/8R1.)
28-31
70-73
CTo3CTo0
External Control Lines 3 to 0 (Output). Output signals generated from the
MT90840 Transmit Path Connection Memory (TPCM). The four serial CTo output
lines represent the contents of the four CT bits in the TPCM, and are clocked at the
parallel port rate (up to 19.44 MHz). See Per-Channel Functions section.
34-41
81-88
PDo7PDo0
Parallel Data Output Port 7 to 0 (Output). These eight outputs carry the parallel
port data bytes in the transmit direction and operate at data rates up to
19.44 Mbyte/s.
5
Zarlink Semiconductor Inc.
MT90840
Data Sheet
Pin Description (continued)
Pin #
Name
Description
89
PPFTi/o
Parallel Port Framing, Transmit (Bidirectional). This signal delineates the start
of a new data frame at the PDo0-7 lines on the transmit parallel port. Normally an
output, when the PFDI bit in the TIM Register is set high PPFT becomes an input,
and is used to receive the frame reference from another MT90840. Used in all
timing modes except TM3.
45-52
92-99
PDi7-0
Parallel Data Input Port 7 to 0 (Input). These eight inputs carry the parallel port
data bytes in the receive direction and operate at data rates up to 19.44 Mbyte/s.
55
6
PCKR
Parallel Port Clock, Receive (Input). This is a 19.44, 16.384, or 6.48 MHz clock
input. It might typically be provided by a high speed framer. PCKR clocks in data
on the receive parallel port (PDi7-0 and PPFRi). In Timing Modes 2, 3, and 4,
PCKR clocks both the transmit and receive parallel ports.
56
7
PCKT
Parallel Port Clock, Transmit (Input). This is a 19.44, 16.384, or 6.48 MHz clock
input. It might typically be provided by a high speed framer. In TM1 PCKT clocks
out the data on the transmit parallel port (PDo0-7, CTo0-3, and PPFTo). In TM2,
TM3, & TM4, this input is ignored.
57
8
PPFRi
Parallel Port Framing, Receive (Input). This 8 kHz frame pulse input determines
the start of a new frame at the PDi0-7 lines of the receive parallel port. It might
typically be connected to the frame pulse output of a high speed framer. In TM3,
PPFRi is the frame sync reference for both the transmit and receive parallel ports.
58
9
TDI
Test Data (Input). JTAG serial test instructions and data are shifted in on this pin
on rising TCK. This pin is pulled high internally when not driven.
59
10
TRST
Test Reset (Input). Asynchronously initializes the JTAG TAP controller, placing it
in the Test-Logic-Reset state. This pin is pulled high internally when not driven.
This pin should be pulsed low on power-up, or held low continuously, to ensure
that the MT90840 is in the normal functional state, and not the test state.
60
11
TCK
Test Clock (Input). Provides the clock to the JTAG test logic. This pin is pulled
high by an internal pull-up when not driven.
61
12
TMS
Test Mode Select (Input). JTAG signal that controls the state transitions of the
TAP controller, sampled on rising TCK. This pin is pulled high by an internal pullup when not driven.
62
13
TDO
Test Data (Output). JTAG serial data is output on this pin on the falling edge of
TCK. This pin is held in a high impedance state when JTAG scan is not enabled.
65
16
SPCKo
Serial Port Clock (Output) In TM2 and TM3, this is a 4.096 MHz clock output
derived from the system 4.096 MHz reference. (As controlled by the C4/8R bit and
the INTCLK bit in the TIM Register.) This output is used to shift data in and out of
the serial port.
84
100
42
In TM1 and TM4, this output is automatically placed in high impedance.
For applications with the serial port running at 8.192 Mbps this output is not used,
and an 8.192 MHz clock source must be supplied at C4/8R1 or C4/8R2.
6
Zarlink Semiconductor Inc.
MT90840
Data Sheet
Pin Description (continued)
Pin #
84
100
Name
Description
66-73
17-24 STo7-STo0 Serial Output Streams 7 to 0 (Bidirectional). Serial TDM data-streams at 2.048,
4.096 or 8.192 Mbps, with 32, 64 or 128 channels respectively per stream. For
2.048 and 4.096 Mbps applications, streams STo0-STo7 can be used, while for
8.192 Mbps, only streams STo0-STo3 are used (512 channel limit). These eight
bidirectional lines can be programmed as inputs or outputs (default) on a perchannel basis.
76-83
32-39
AD0-AD7
Multiplexed Address/Data Bus (Bidirectional). These I/O lines provide an 8-bit
interface to a microprocessor for control and monitoring of the MT90840. These
pins function as eight input address lines to the Address Latch circuit as well as
eight data I/O lines.
84
40
R/W \ WR
Read/Write \ Write (Input). In Motorola multiplexed-bus mode this input is
R/W, which controls the direction of the data bus lines (AD0-AD7) during a
microprocessor access. In Intel/National multiplexed-bus mode this input is WR,
an active low signal which configures the data bus lines (AD0-AD7) as inputs
during a microprocessor write access.
1,11
24,32,
43,53,
64,74
15,25,
41,55,
68,74,
90,10
0
VSS
Ground.
2, 12,
25,33
44,54,
63,75
5, 14,
26,42
56,69,
75,91
VDD
+5 Volt Power Supply.
Functional Description
The MT90840 Distributed Hyperchannel Switch is a large switching, multiplexing, and rate-adapting device. The
MT90840 bridges serial-bus telecom components, using the Zarlink ST-BUS or other industry-standard serial
buses, onto a higher speed “backbone”. Mixed data, voice and video signals can be time-interchanged or
multiplexed from serial Time Division Multiplexed (TDM) streams onto a high speed parallel bus. The parallel bus
can be used for interconnect, or an external framer can be connected to the parallel bus to access serial
isochronous backbones operating at up to 155 Mbps SONET rates (STS-3).
The MT90840 Distributed Hyperchannel Switch supports real-time multimedia applications through constant delay
switching. Multimedia data at N x 64 kbps rates uses N bytes (“time slots”, or “channels”) per 125 µsec frame. This
is also referred to as hyperchannel data. To ensure the integrity of data at N x 64 kbps rates, the network must
ensure that the N bytes in a given input frame remain together as a frame, and arrive at the destination as a frame.
The MT90840 supports this requirement by providing constant delay (frame integrity) which ensures that the
multiple time slots of associated data remain in the intended order.
Total TDM channel capacity of the MT90840 at maximum data rates is:
•
512 serial input time slots,
•
512 serial output time slots,
•
2430 parallel input time slots, and
7
Zarlink Semiconductor Inc.
MT90840
•
Data Sheet
• 2430 parallel output time slots.
The number of time slots available is dependent upon the selected data rates, and is reduced at lower data rates.
Figure 1 shows the MT90840 functional block diagram. The figure shows the TDM data paths and the device
interfaces.
The MT90840 has three main TDM data paths:
•
Transmit Path: serial port input (STi) to parallel port output (PDo),
•
Receive Path: parallel port input (PDi) to serial port output (STo),
•
Bypass and Parallel-Switching: PDi to PDo.
In addition, Zarlink Message Mode capabilities allow the user to force data on TDM output time slots and to monitor
TDM input time slots through the microprocessor port.
The MT90840 has four main interfaces:
•
the serial TDM bus interface (STi, STo and timing),
•
the parallel TDM bus interface (PDi, PDo and timing) with programmable control outputs (CTo),
•
the microprocessor (CPU) interface,
•
the test interface (JTAG).
The MT90840 supports four major timing/switching modes:
•
TM1/Ring Master: PDo timing slaved to STi/o timing, PDi timing elastic;
•
TM2/Ring Slave: PDo and STi/o timing slaved to PDi;
•
TM3/Bus Slave: PDo and PDi timing tied together, STi/o timing slaved to parallel bus;
•
TM4/Parallel Switching: parallel channel switching from PDi to PDo.
Other features of the MT90840 are programmable for individual TDM channels on the serial and parallel ports (perchannel features):
•
Zarlink Message Mode,
•
Per-channel output enable,
•
Per-channel bypass (parallel bus),
•
Programmable CTo control outputs (parallel bus),
•
Per-channel direction control (serial bus).
8
Zarlink Semiconductor Inc.
MT90840
Data Sheet
Device Operation
Time Slot Interchange Operation (Switching)
The MT90840 provides access and time slot interchange (switching) functions between the serial and parallel TDM
data ports. Switching is provided on three paths: transmit (serial input to parallel output), receive (parallel input to
serial output) and bypass/parallel-switching (parallel input to parallel output). Switching functions between serial
data streams are not provided.
The MT90840 guarantees wideband or hyper-channel data integrity through the switch by using constant delay
switching. This is done by storing a full frame (125 µsec) of data at the input rate and then, under control of the
Connection Memory for that path, reading the frame at the output data rate (frame integrity). Therefore the Transmit
Path and the Receive Path each have separate Data and Connection Memories.
Switching in a given data path is controlled by programming the Connection Memory for that path. Each output time
slot has a control-address in the path’s Connection Memory. Each input time slot has an address-value in the path’s
Data Memory. A given output time slot is controlled by programming the Connection Memory control-address with
the address-value of the source input time slot. At the same control-address the output time slot is enabled or tristated and other per-channel functions set up. Thus each output time slot is individually controlled, and any given
input time slot might be copied to one, several, or none of the output time slots.
Frame Boundary Established by F0
C4/8R1&2
(4 MHz)
Serial I/O
2 Mbps
Serial I/O
4 Mbps
Ch. 31 Bit 1
Ch. 63 Bit 2
Ch. 31 Bit 0
Ch. 63 Bit 1
Ch. 0 Bit 6
Ch. 0 Bit 7
Ch. 63 Bit 0
Ch. 0 Bit 7
Ch. 0 Bit 6
C4/8R1&2
(8 MHz)
Serial I/O
8 Mbps
ch.127
b3
ch.127
b2
ch.127
b1
ch.127
b0
ch. 0
b7
ch. 0
b6
ch. 0
b5
ch. 0
b4
Figure 3 - Serial Port Interface Functional Timing
9
Zarlink Semiconductor Inc.
Ch. 0 Bit 5
MT90840
Data Sheet
Frame Boundary Established by PPFRi
PCKR
PPFRi
Ch. n-2
PDi0-7
Ch. n-1
Ch. n
Ch. 0
Ch. 1
Ch. 2
Frame Boundary Established by PPFTi/o
PCKR or PCKT
(TCP bit = 0)
PPFTi/o
(PPFP bit =1)
Ch. n-2
PDo0-7
Ch. n-1
Ch. 0
Ch. n
Ch. 1
Ch. 2
Notes: In TM1, 2 and 4 PPFRi and PPFT are not simultaneous.
Terminal count “n” = 2429, 2047, or 809.
Figure 4 - Parallel Data Port Functional Timing
Transmit Path
The Transmit Path is from the serial inputs, through the Transmit (Tx) Path Data Memory, to the parallel outputs
(PDo0-7). This path is controlled by the contents of the Tx Connection Memory. The Tx Connection Memory is
programmed, for each output time slot, with the address-value of the source channel to be read out of the Tx Data
Memory. Up to 512 channels of serial input can be switched to up to 2430 channels of parallel output.
Transmit Path Connection Memory
The Tx Path Connection Memory is structured as 2430 words of 16 bits. This supports up to 2430 DS0 channels for
parallel rates up to 19.44 Mbyte/s (155 Mbps). The Tx Path Connection Memory is accessed as two-sub memories:
High and Low. The Connection Memory Low (2430 X 8) is the low byte of the word, and is programmed with the
address-value of the serial-input source channel. The Connection Memory High (2430 x 8) is the high byte of the
word. Connection Memory High holds the high-order bit(s) of the source address-value, and is also programmed to
control per-channel functions such as output driver-enable and programmable control outputs.
10
Zarlink Semiconductor Inc.
MT90840
Data Sheet
Transmit Path Data Memory
The Tx Path Data Memory is structured as 512 words of 8 bits. Serial input time slots are converted to parallel bytes
and copied to the Tx Path Data Memory sequentially, serial-stream by serial-stream. The lowest address of the Tx
Path Data Memory is STi0-channel0, the next is STi0-channel1, and so on. At 2 Mbps, with 32 channels per STi pin,
STi1-channel0 would be 32 addresses higher than STi0-channel0. The Tx Path Data Memory is read out to the
parallel outputs by the Tx Connection Memory.
Receive Path
The Receive Path is from the parallel inputs (PDi0-7), through the Receive (Rx) Path Data Memory, to the serial
outputs. This path is controlled by the contents of the Rx Path Connection Memory. The Rx Path Connection
Memory is programmed, for each output time slot, with the address-value of the source channel to be read out of
the Rx Path Data Memory. Up to 2430 channels of parallel input can be switched to up to 512 channels of serial
output. Each output byte, whether switched data or message mode data, is read from memory and passed to the
parallel-to-serial converters, and then driven out the serial port.
Receive Path Connection Memory
The Rx Path Connection Memory is structured as 512 words of 16 bits. This supports up to 512 DS0 channels. The
Rx Path Connection Memory is accessed as two sub-memories: High and Low. The Connection Memory Low (512
x 8) is the low byte of the word, and is programmed with the address-value of the parallel-input source channel. The
Connection Memory High (512 x 8) is the high byte of the word. Connection Memory High holds the high-order bits
of the source address-value, and is also programmed to control per-channel functions such as output driver-enable
and direction-control.
Receive Path Data Memory
The Rx Path Data Memory is structured as 2430 words of 8 bits (1 byte). Parallel input time slots are copied to the
Rx Path Data Memory sequentially. The Rx Path Data Memory is read out to the serial port by the Rx Path
Connection Memory.
Bypass/Parallel-Switching Path
The Bypass/Parallel Switching path is from parallel input to parallel output. Data received at the parallel inputs
(PDi0-7) is copied to the Rx Path Receive Memory, and may be passed to the parallel outputs (PDo0-7) under
control of the Tx Path Connection Memory.
Bypass
In ring timing modes (TM1 and TM2) this is a bypass path. When the Bypass bit (PPBY) for a given parallel output
channel is set in the Tx Path Connection Memory, the same-address parallel input channel is copied (bypassed) to
that parallel output channel. This allows data channels not destined for the local node to be bypassed to the output
port and down the ring. “Broadcast” channels destined for every node can also be bypassed, since PPBY is an
output control, and it does not affect the availability of the Receive Parallel data for switching to the serial port or
monitoring through the CPU interface.
Parallel Switching
In Parallel Switching Mode (TM4) this is a switching path, and the Tx Path Connection Memory is programmed to
switch parallel inputs to parallel outputs. For each parallel output channel control-address, the Tx Path Connection
Memory is programmed with the 12-bit address-value of the desired parallel input channel.
11
Zarlink Semiconductor Inc.
MT90840
Data Sheet
Serial Data Port
The serial port consists of 16 bidirectional serial data lines (STo0-7, STi0-7), two reference input clock pins
(C4/8R1, C4/8R2), one serial clock output (SPCKo) and a bidirectional frame synchronization signal (F0i/o). The
STi pins are the default inputs, but the user can program the direction of the pins on a per-channel basis in the Rx
Path Connection Memory.
The serial port modes are controlled by the DR bits and the FDC bit in the IMS register, and are:
•
2.048 Mbps Balanced: 8 inputs and 8 outputs per serial time slot (FDC = 0),
•
2.048 Mbps Add/Drop: 16 serial I/O individually programmed per time slot (FDC = 1),
•
4.096 Mbps: 8 inputs and 8 outputs per time slot,
•
8.192 Mbps: 4 inputs and 4 outputs per time slot.
Figure 3 shows the different data rate configurations for the MT90840 serial port.
In addition the user can specify the placement and polarity of the output frame pulse F0o as ST-BUS or GCI
compatible, using the SPFP bit in the GPM register. In TM1, the MT90840 automatically detects ST-BUS or GCI
serial bus modes, based on the polarity of F0i. The user can also specify which of the two input clock pins - C48R1
or C48R2 - to use as the serial port clock source, using the C4/8R bit in the TIM register.
The user can define the direction of each time slot of the serial port. This per-channel direction control feature is
controlled by the DC bit in the Rx Path Connection Memory High. This is ideal for applications in Computer
Telephony Integration (CTI) where per-channel direction control is required within telephony servers.
2.048 Mbps Balanced Mode
The 2.048 Mbps Balanced mode has 8 inputs and 8 outputs active during each serial-byte-period or “time slot”. At
2.048 Mbps, each STi/o pin has 32 8-bit channels per 125 µsec frame, with each individual channel at 64 kbps.
(1/125µsec X 8 bits = 64 kbps, 32 x 64 kbps = 2.048 Mbps). This mode supports 256 serial input channels and 256
serial output channels. This mode is “balanced” in that there are always 8 inputs and 8 outputs during a time slot. If
a specific time slot in an output stream (e.g. STo0-channel7) is programmed in the Rx Path Connection Memory as
an input, the corresponding time slot on the equivalent input stream (i.e. STi0-channel7) is automatically an output.
The serial clock for this mode is 4.096 MHz.
2.048 Mbps Add/Drop Mode
The 2.048 Mbps Add/Drop mode (FDC bit high) has 16 bidirectional streams active during each time slot. This
mode allows up to 512 input channels, or up to 512 output channels, or any mix of channels totalling 512 channels.
Per-channel direction control in the Rx Connection Memory specifies the direction of all 512 serial channels from
STo0-channel0 up to STi7-channel31.
4.096 Mbps Mode
The 4.096 Mbps mode has 8 inputs and 8 outputs active during each time slot. At 4.096 Mbps each STi/o pin has
64 channels of 64 kbps. This mode supports 512 serial input channels and 512 serial output channels. The serial
clock is 4.096 MHz. Per-channel direction control in this mode is the same as the 2.048 Mbps balanced mode.
8.192 Mbps Mode
The 8.192 Mbps mode has 4 inputs and 4 outputs active during each serial byte period. At 8.192 Mbps, each STi/o
pin has 128 channels. This mode supports 512 serial input channels and 512 serial output channels. The serial
clock for this mode is 8.192 MHz. Per-channel direction control in this mode is the same as the 2.048 Mbps
balanced mode.
12
Zarlink Semiconductor Inc.
MT90840
Data Sheet
Serial Port Clock Signals
Depending on the Timing Mode selected, the serial port clock is either an input, or an output derived from a
reference clock. In modes where the serial clock is derived by the MT90840 from a reference clock, the serial port
clock output appears at SPCKo. The reference clock is either PCKR (if INTCLK is high), or one of C4/8R1 or
C4/8R2. The C4/8R bit of the Timing Mode Register is used to select which of C4/8R1 or C4/8R2 will be the clock
source or reference pin. Switching between clock sources during device operation will cause temporary TDM data
errors.
Internal 4.096 MHz Clock Generator
For TM2 applications running at 19.44 or 16.384 MHz rates on the parallel port, an internal divider can be used to
generate a 4.096 MHz clock from the PCKR clock input. The internal divider can not be used in applications where
the parallel port operates at 6.480 Mbyte/s rates. The INTCLK bit in the TIM Register enables the internal divider,
and the SPCKo output (and internal 4.096 MHz clocks) are driven by the clock divided-down from PCKR. At
16.384 MHz, this is a simple divide-by-4, and the SPCKo output jitter will depend on the PCKR input jitter. At
19.44 MHz, the SPCKo output jitter will be larger as the divider switches between rising and falling edges of PCKR.
The serial port timing and F0o frame pulse are tightly slaved to PPFRi when INTCLK is set high.
Serial Frame Pulse
In TM1, the MT90840 receives the frame reference (F0i) from an external source, and the MT90840 senses the
polarity of the frame pulse and adapts the device timing to the appropriate (ST-BUS or GCI) format.
In TM2 and TM3, the MT90840 outputs the serial port frame pulse (F0o). Positive (GCI) or negative (ST-BUS)
frame pulse formats, and the associated clock polarity, can be selected for the F0o signal by programming the
SPFP bit in the GPM Register. This flexibility allows the MT90840 to be employed with different serial bus formats.
In applications which require a large number of serial channels in TM2, it is possible to operate multiple MT90840s
in parallel using the SFDI control bit (in the TIM register). To allow the MT90840s to synchronize their internal
timing, all of the MT90840s are connected to the same C4/8 reference source, and one MT90840 in normal TM2
(SFDI set low) supplies F0 to one or more MT90840s in TM2 with SFDI set high. With SFDI set high, F0 becomes
an input, and this allows the MT90840 driving F0 to control the timing of one or more other MT90840s. If the internal
4.096 MHz clock divider is used (INTCLK high) it is not necessary to use the SFDI control, as the serial port timing
and F0o frame pulse of each parallel MT90840 will be tightly slaved to PPFRi when INTCLK is set high.
Should the input framing at F0i cease while the C4/8 clock continues to run, the MT90840 will continue to function
as if the frame pulse was asserted after the normal number of clock cycles (free run). If F0i re-commences the
MT90840 will immediately sync to F0i, but changes in the F0i interval will temporarily disrupt the TDM data streams.
If the F0i input is held asserted, the serial I/O will “lock up” and operation will be disrupted.
Parallel Data Port
The MT90840 parallel port is composed of an 8-bit wide Parallel Data Output Port (PDo0-7), a 4-bit wide Control
output port (CTo0-3), an 8-bit wide Parallel Data Input Port (PDi0-7), a Receive Frame sync signal (PPFRi) and a
Transmit Frame sync signal (PPFT), and Transmit (PCKT) and Receive (PCKR) Clocks.
The Parallel Port Rates are controlled by the PPS bits in the IMS register, and are:
•
19.44 Mbyte/s (2430 channels),
•
16.384 Mbyte/s (2048 channels), and
•
6.48 Mbyte/s (810 channels).
The user can further specify the features of the parallel TDM port, including:
•
the edge of the parallel port clock used to transmit data and PPFTo (see TCP bit in the TIM register),
•
the polarity of the Parallel Port Frame Transmit pulse PPFT (see PPFP bit in the GPM register),
13
Zarlink Semiconductor Inc.
MT90840
•
Data Sheet
the use of PPFT (normally an output) as an input in TM1, if the application requires multiple MT90840
devices to operate in parallel (see PFDI bit in the TIM register).
The parallel port of the MT90840 is flexible enough to interface to a variety of applications. It can be connected to a
framer to access a serial transport backbone running at up to 155 Mbps. It can be connected to a backplane-type
parallel bus. It can share a parallel bus with other devices, using the control outputs (CTo0-3) and the per-channel
tristate function to share access to the bus.
Parallel Port Clock Signals and Framing
The MT90840's PPFRi (Parallel Port Frame pulse Receive input) and PPFTi/o (Parallel Port Frame pulse Transmit
i/o) signals synchronize the MT90840 to the high speed data frame. Receive data is clocked in at the Parallel Data
inputs (PDi0-7) by the Parallel port Receive ClocK (PCKR), as framed by Receive Parallel Port Frame input
(PPFRi). In TM2, TM3 and TM4, PCKR also clocks the Parallel Data outputs (PDo0-7), with the framing in TM2 and
TM4 indicated by the PPFTo output. In TM1, the Parallel Data outputs are clocked out by PCKT, with the framing
indicated by PPFTo. Alternatively, the Transmit framing can be controlled by the PPFTi input if the PFDI bit in the
TIM register has been set high, to enable multiple MT90840s to operate in parallel in TM1.
Should the input framing at PPFRi cease while the PCKR clock continues to run, the MT90840 will continue to
function as if the frame pulse was asserted after the normal number of clock cycles (free run). If PPFRi recommences, the MT90840 will immediately sync to PPFRi, but any change in the framing interval will temporarily
disrupt the TDM data streams, and trigger the PPCE interrupt bit. PPCE will be triggered by PPFRi moving from the
expected time, but PPCE will not be triggered by a missing PPFRi. If the PPFRi input is held asserted, the parallel
I/O will “lock up” and operation will be disrupted (including CPU access to the TPCM).
The PPFTi framing in TM1 with PFDI=1 operates similarly, using PCKT, but the PPCE interrupt does not monitor
PPFTi. Instead, the TXPAA bit indicates that the PPFTi input is out of phase with F0i.
Output Driver Enable Control Capability
The MT90840 provides a bit (ODE) in the IMS Register that places all data outputs of the device (parallel and
serial) in a high impedance state. The ODE bit (Output Drive Enable) is automatically set low by the reset input
pulse applied to the device during system power up. When low, the ODE bit disables all TDM outputs of the
MT90840 while Connection Memory initialization is performed by the CPU. This function is useful to avoid data
collision when the MT90840 is sharing a transmit parallel bus with other devices. When ODE is set high, individual
parallel and serial port time slots are controlled by the OE bits in TPCM High and RPCM High.
Timing and Switching Control
The MT90840 supports four major timing/switching modes:
•
TM1/Ring Master: PDo timing slaved to STi/o timing, Receive Path has elastic buffer enabled;
•
TM2/Ring Slave: STi/o timing slaved to PDi timing, fixed delay in Receive Path;
•
TM3/Bus Slave: PDo and PDi tied together, STi/o timing slaved to parallel bus timing;
•
TM4/Parallel Switching: 2430 (or 2048) channel switching from PDi to PDo.
The TM1-0 bits in the TIM Register are used to select the timing modes. The PFDI and SFDI bits in the same
register can be used to enable parallel-device sub-modes of TM1 and TM2 respectively. In all MT90840 timing
modes, the throughput delay when performing time interchange functions of grouped channel data is constant,
maintaining the frame integrity of the input and output data.
14
Zarlink Semiconductor Inc.
MT90840
Data Sheet
Timing Mode 1 (TM1) - Ring Master
Asynchronous Parallel Port With ST-BUS Clock Master
Timing Mode 1 is used where the main TDM clock reference resides on the serial port side of the system. (An
example is a node which is the clock master on a ring network.) Timing on the transmit parallel port is tightly tied to
the serial port. The receive parallel port timing is elastic; there is an elastic buffer in the Receive Path and the
Bypass Path. See Figure 5a for a connection example.
MT90840
RX Clock
8 kHz RX
8 Data RX
8 kHz TX
8 Data TX
PCKR
PPFRi
PDi0-7
STi0-7
STo0-7
PCKT
ST-BUS
Components
8 kHz
F0i
PPFTo
PDo0-7
8 STi/o 0-7
8 STi/o 0-7
8 kHz
Source
4.096
or 8.192 MHz
C4/8R1
CPU
TX Clock
PLL
Figure 5a - Timing Mode 1 Configuration
In TM1, the MT90840 receives the serial port frame pulse (F0i) and serial clock (C4/8R1 or C4/8R2). The MT90840
then generates the parallel port output frame pulse (PPFTo) synchronized to F0i. The transmit parallel port is fixed
in phase relative to the serial port. (A fixed offset of 3.8 µsec exists between F0i and PPFTo due to serial-to-parallel
conversion.) The transmit path does not provide an elastic buffer, and therefore the parallel port TX clock (PCKT)
must be tightly locked (in frequency) to the serial port C4/8 and F0i clocks. (Jitter less than +/- 100nsec.)
The receive parallel port timing may be of any phase relative to the serial and transmit-parallel ports in TM1. This
allows for flexible round-trip data delays in star or ring type networks. An elastic buffer on the receive parallel port
compensates for the difference in phase between PPFRi/PCKR and F0i/C4. The elastic buffer can also tolerate up
to 50 µsec +/- 25 µsec) of clock drift and jitter before the buffer re-syncs and Rx Path data is corrupted. (Data
corruption is flagged by the FSA interrupt source.) The Bypass Path data (PDi to PDo) also passes through the
elastic buffer in TM1.
In TM1, the MT90840's SPCKo clock output is not used.
TM1 Multiple-MT90840 Sub-Mode (PFDI)
For TM1 applications which require more serial channels than are provided by a single MT90840, it is possible to
operate multiple MT90840 in parallel. To do this, one MT90840 must control the F0i-to-PPFTo timing (normal TM1),
and the remaining MT90840s must synchronize to the first by using PPFTi as an input reference. The device
providing the reference will have the PFDI bit in the TIM Register set low (normal TM1). All other MT90840s will
have PFDI set high (forcing PPFT to be an input).
Figure 5b shows this mode using two MT90840s; additional MT90840s (with PFDI set high) may be added. This
sub-mode allows the serial ports of the multiple MT90840 to share one timing source, and the synchronized parallel
output ports to be connected together on one bus.
The TM1 Multiple-MT90840 sub-mode is not available for operation at 6.48 Mbyte/s.
15
Zarlink Semiconductor Inc.
MT90840
MT90840
RX Clock
PCKR
PPFRi
PDi0-7
8 kHz RX
RX Data
TX Clock
8
PFDI = 0
STo0-7
ST-BUS
Components
8 kHz
F0i
PPFTo
PDo0-7
TX Data
8 STi/o 0-7
8 STi/o 0-7
STi0-7
PCKT
8 kHz TX
8
Data Sheet
8 kHz
Source
4.096
or 8.192 MHz
C4/8R1
CPU
MT90840
PCKR
PPFRi
PDi0-7
TX Clock
8 kHz TX
8
Data TX
PFDI = 1
8 STi/o 0-7
8 STi/o 0-7
STi0-7
STo0-7
PCKT
8 kHz
F0i
PPFTi
PDo0-7
PLL
4.096
or 8.192 MHz
C4/8R1
TX Clock
Figure 5b - TM1 Multiple-MT90840 Configuration
Timing Mode 2 (TM2) - Ring Slave
Asynchronous Parallel Port With ST-BUS Clock Slave
Timing Mode 2 is used where the main TDM clock reference resides on the parallel port side of the system. (An
example is a node on a ring which is slaved to the ring clock.) Timing on the serial port is tightly tied (slaved) to the
receive parallel port, and the transmit parallel port is clocked by the receive parallel port clock. In TM2, the PCKT
input is not used. See Figure 6a for a connection example.
CPU
MT90840
8 kHz TX
8
8
8 kHz
Source
Data TX
TX/RX Clock
Data RX
8 kHz RX
PPFT
PDo0-7
STi0-7
STo0-7
PCKR
PDi0-7
PPFRi
SPCKo
C4/8R1 & 2 F0o
STi/o 0-7
STi/o 0-7
8
8
4.096 MHz
8 kHz
4.096 MHz or
8.192 MHz
PLL
(8.192 MHz)
Note: the use of an external PLL is optional at 4.096 MHz (2.048 Mbps and 4.096 Mbps)
Figure 6a - Timing Mode 2 Configuration
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Zarlink Semiconductor Inc.
ST-BUS
Components
MT90840
Data Sheet
In TM2, the MT90840 timing is controlled by the parallel port frame pulse (PPFRi) and clock (PCKR). The MT90840
generates the parallel port output frame pulse (PPFTo) and the serial port output frame pulse (F0o) locked to
PPFRi. Both the transmit parallel port and the serial port are fixed in phase relative to the receive parallel port, and
therefore no elastic buffer is required. A fixed offset exists between PPFRi and F0o due to parallel-to-serial
conversion, and between F0o and PPFTo due to serial-to-parallel conversion delay. Total offset between PPFRi and
PPFRo is about 12 µsec (and the Bypass Path data delay is therefore also about 12 µsec).
The transmit path does not provide an elastic buffer, and therefore the serial port clock must be tightly locked (in
frequency) to the parallel port clock (PCKR). (Jitter less than +/- 100nsec.) This may be achieved in one of two
ways: use of the internal clock divider (INTCLK set high), or use of an external PLL or DPLL, with C4 phasecorrection performed by the MT90840.
Internal 4.096 MHz Clock Divider
For TM2 applications at 19.44 or 16.384 MHz rates on the parallel port, and 4.096 MHz on the serial port, the
internal clock divider can be enabled. The clock divider can generate the required serial port clock outputs from the
parallel port clock inputs. When enabled in TM2, the clock divider will provide 4.096 MHz (SPCKo) and 8 kHz (F0o)
timing to the serial port that is rigidly locked to the PCKR and PPFRi clocks at the parallel port. The clock divider is
enabled by setting the INTCLK bit high (in the TIM Register). The clock divider can not be used in applications
where the parallel port operates at 6.480 Mbyte/s rates.
External PLL and C4 Phase-Correction
The MT90840 also supports the use of an external PLL (e.g. MT9041/2) to generate 4.096 or 8.192 MHz from the
parallel port timing reference. At 4.096 MHz the generated clock must be input to the MT90840 (at C4/8R1 or
C4/8R2) for phase monitoring and correction. The phase-corrected 4.096 MHz clock is then output on the SPCKo
pin. Should the phase of the C4clock input (relative to the PPFRi framing input) drift more than approximately +/100nsec, the MT90840 will apply an additional correction and indicate possible data corruption with the RXPAA
interrupt source. At 8.192 MHz, the generated clock is input to the MT90840 (at C4/8R1 or C4/8R2), and is also
supplied directly to the serial bus (the SPCKo output is not used at 8.192 MHz). The serial port frame pulse (F0o)
will be slaved to the parallel port frame pulse (PPFRi), and will be clocked out by SPCKo, or the 8.192 MHz clock,
as appropriate.
TM2 Multiple-MT90840 Sub-Mode (SFDI)
For TM2 applications which require more serial channels than are provided by a single MT90840, it is possible to
operate multiple MT90840s in parallel. Multiple-MT90840 operation is automatic if INTCLK is selected, but if an
external PLL is used, the serial port timing of the MT90840s must be synchronized. To do this, one MT90840
controls the PPFRi-to-F0o timing and C4 phase-control (normal TM2), and the remaining MT90840s must
synchronize to the first by using F0 as an input reference. The device providing the reference will have the SFDI bit
in the TIM Register set low (normal TM2). All other MT90840s will have SFDI set high (forcing F0 to be an input).
Figure 6b shows this mode using two MT90840s; additional MT90840s (with SFDI set high) may be added. This
sub-mode allows the serial ports of the multiple TM2 MT90840s to share one timing source. The transmit parallel
port outputs are always synchronized to PPFRi in TM2, so the multiple MT90840s can also be connected together
on one parallel output bus.
The TM2 Multiple-MT90840 sub-mode is not available for operation at 6.48 Mbyte/s.
17
Zarlink Semiconductor Inc.
MT90840
Data Sheet
CPU
MT90840
8 kHz TX
8
Data TX
TX/RX Clock
8
8 kHz
Source
Data RX
8 kHz RX
PPFT SFDI = 0
PDo0-7
STi0-7
STo0-7
PCKR
PDi0-7
PPFRi
STi/o 0-7
STi/o 0-7
8
8
4.096 MHz
SPCKo
C4/8R1 & 2 F0o
ST-BUS
Components
8 kHz
4.096 MHz or
8.192 MHz
(8.192 MHz)
PLL
8
8
Data TX
Data RX
PPFT
PDo0-7
C4/8R1 & 2
STi0-7
STo0-7
8
8
PCKR
PDi0-7
PPFRi
STi/o 0-7
STi/o 0-7
4.096 MHz
SPCKo
F0i
SFDI = 1
MT90840
CPU
Figure 6b - TM2 Multiple-MT90840 Configuration
Timing Mode 3 (TM3) - Bus Slave
Synchronous Parallel Port With ST-BUS Clock Slave
Timing Mode 3 is used where the main TDM clock reference resides on the parallel port side of the system, and
where the receive parallel port and the transmit parallel port are aligned. (An example is a node on a backplane.)
Timing on the serial port is tightly tied to the receive parallel port, and the transmit parallel port is clocked by the
receive parallel port clock. In TM3, PCKT and PPFTo are not used. See Figure 7 for a connection example.
In TM3, the MT90840 timing is controlled by the parallel port frame pulse (PPFRi) and clock (PCKR). The MT90840
generates the serial port output frame pulse (F0o) locked to PPFRi. TM3 is similar to TM2 with two main
differences: the parallel Bypass Path is disabled, and the parallel port receive and transmit buses are synchronized
and both aligned with PPFRi. A fixed offset exists between F0o and PPFRi due to serial-to-parallel conversion. The
MT90840 will align F0o so that it proceeds PPFRi by 3.8 µsec.
In TM3 the internal clock divider circuit is always enabled, regardless of the state of the INTCLK bit (C4/8R1 and
C4/8R2 are unused). Therefore TM3 is limited to 19.44 and 16.384 Mbyte/s parallel port rates, and 2.048 and
4.096 Mbps serial port rates.
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Zarlink Semiconductor Inc.
MT90840
Data Sheet
MT90840
Aligned
Frames
8 kHz
Source
8
PDi0-7
PDo0-7
8
8 kHz REF
STi0-7
STo0-7
8
8
PPFRi
RX/TX Clock
F0o
SPCKo
PCKR
STi/o 0-7
STi/o 0-7
ST-BUS
Components
8 kHz
4.096 MHz
CPU
Figure 7 - Timing Mode 3 Configuration
Timing Mode 4 (TM4) - Parallel Data Switching
Timing Mode 4 is used to provide switching of up to 2430 parallel input channels to the same number of parallel
output channels. Parallel TDM data is clocked in at PDi0-7 by PCKR, framed by PPFRi. Switching is performed as
programmed in the Tx Path Connection Memory, and data is output on PDo0-7, framed by PPFTo and clocked by
PCKR. See Figure 8 for connection details.
In TM4, PPFTo and PDo0-7 are offset (delayed) from PPFRi and PDi0-7 by a fixed 4 clock cycles (3.5 clock cycles
if the TCP bit is high). All the serial port data and timing signals, and PCKT, are unused in TM4. The internal clock
divider is used to generate an internal C4 clock to allow CPU reads from the RPDM. TM4 is only available for 19.44
and 16.384 Mbyte/s rates.
Clock Reference
MT90840
8
Parallel Data In
PDi0-7
8 kHz RX
8 kHz
Source
19.44 or 16.384 MHz (RX)
PDo0-7
Parallel Data Out
8
PPFTo TX 8 kHz REF
PPFRi
PCKR
CPU
Figure 8 - Timing Mode 4 Configuration
MT90840 Throughput Delay
In many isochronous applications it is important to know and/or limit the delay of data. Table 1 summarizes the data
throughput delay values for all timing modes of the MT90840. It is worth noting that the worst-case “round-trip”
delays are not as large as the sum of the worst-case delays on the individual links. This is shown by the last 5 rows
of Table 1, which give the delays for some representative two MT90840 setups.
MT90840 Per-channel Functions
Several functions of the MT90840 are programmable for each individual parallel channel or serial channel. Perchannel functions on the parallel port side are programmed in the Transmit Path Connection Memory High (TPCM
High), and per-channel functions on the serial port interface are programmed in the Receive Path Connection
Memory High (RPCM High). On the parallel port these per-channel features are Bypass, Control Outputs, Output
19
Zarlink Semiconductor Inc.
MT90840
Data Sheet
Enable, and Message Mode. On the serial port the per-channel features are Output Enable, Message Mode and
Direction Control. These functions are generally available in all of the data rates and timing/switching modes.
Per-channel Bypass on the Parallel Port
This feature, when enabled, causes the specific individual parallel output channel at PDo to transmit the data
received at the same number input channel at PDi. This can be used to perform a bypass (on a ring) or a loopback
(in a star). This feature is only provided in Timing Modes 1 and 2. In TM2 the data-delay from PDi to PDo is fixed (as
is the delay between PPFRi and PPFT). In TM1 the data-delay is elastic (and dependent on the timing of PPFRi
and F0i).
The per-channel bypass feature is controlled by the PPBY bits of the TPCM High as explained in the register
section. If the PPBY bit is HIGH at a specific TPCM address, the corresponding parallel output will transmit the data
received in the corresponding input channel. When the PPBY bit is LOW, the corresponding output channel can be
used for message-mode data, or for switched-data from the serial port. A bypass input channel is still copied to the
Receive Path Data Memory, and may also be switched to the serial port, or read by the CPU from the Receive Path
Data Memory.
The MT90840 per-channel output-enable and message-mode bits have higher priority than the PPBY bit.
Mode
Data Rates
Minimum Delay
Total Throughput Delay
TM1, TM2,
or TM3 S/P
All
Dmin = 7.7 µsec
Note 1
D = Dmin + 1 frame + Po - Si = 132.7 µsec + Po - Si
Min. 7.7 µsec, Avg. 133 µsec, Max. 258 µsec
TM1P/S
All
Dmin = ELDmin
= 4.4 µsec
Note 2
D = 1 frame + ELD + So - Pi = 125 µsec + ELD + So - Pi
Min. 4.4 µsec, Max. 379 µsec
TM2 P/S
All
Dmin = 4.3 µsec
Note 1
D = Dmin + 1 frame + So - Pi = 129.3 µsec + So - Pi
Min. 4.3 µsec, Avg. 129 µsec, Max. 254 µsec
TM3 P/S
All
Dmin = 1 frame 7.7 µsec
= 117.3 µsec
T = Dmin + 1 frame + So - Pi = 242.3 µsec + So - Pi
Min. 117 µsec, Avg. 242 µsec, Max. 367 µsec
TM1 P/P
(Bypass)
All
Dmin = 12 µsec + 1
frame
= 137 µsec
Note 2
D = 7.7 µsec + 1 frame + ELD
Min.137 µsec, Max. 262 µsec
TM2 P/P
(Bypass)
19.44 Mbyte/s
16.384 Mbyte/s
6.480 Mbyte/s
TM4 P/P
(Switching)
19.44 & 16.384
Mbyte/s
Dmin = {3.5 or 4}
PCKR cycles
(TCP bit = 1 or 0)
D = Dmin + 1 frame + Po - Pi
Min. < 0.3 µsec, Avg. 125 µsec, Max. 250 µsec
TM1 S/P +
TM2 P/S
All
Dmin = 12 µsec + 1
frame
= 137 µsec
D = 12 µs + 2 frames + Transmission + So - Si
= 262 µsec + Transmission + So - Si
TM2 S/P +
TM1 P/S
All
Dmin = 12 µsec + 1
frame
= 137.4 µsec
D = 12 µsec + 2 frames + Transmission + ELD + So - Si
= 262 µsec + Transmission + ELD + So - Si
D = {235 or 235.5} PCKR cycles = 12 µsec
D = {199 or 199.5} PCKR cycles = 12 µsec
D = {80 or 80.5} PCKR cycles = 12 µsec
Note 3
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Zarlink Semiconductor Inc.
MT90840
Mode
Data Rates
Minimum Delay
Data Sheet
Total Throughput Delay
TM1 S/P +
TM2 P/S +
TM2 S/P +
TM1 P/S
All
Dmin = 4 frames
= 500 µsec
D = (2 X 12) µsec + 4 frames + 2 X Transmission + ELD +
So - Si = {5 or more integral frames} + So - Si
(Note 4)
TM1 S/P +
TM2 Bypass
+ TM1 P/S
All
Dmin = 2 frames
= 250 µsec
D = (3 X 12) µsec + 2 frames + 2 X Transmission + ELD +
So - Si
= {3 or more integral frames} + So - Si
(Note 4)
TM3 S/P +
TM3 P/S
All
Dmin = 250 µsec
D = (7.7 + 117.3) µsec + 2 frames + So - Si
= 375 µsec + So - Si
Min. 250 µsec, Avg. 375 µsec, Max. 500 µsec (Note 4)
Table 1 - MT90840 Throughput Delay Summary
Naming rules:
ELD:
ELastic Delay, measured from PPFRi to F0i (4.4 to 129.4 µsec).
P/S:
Parallel-to-Serial data path.
Pi:
Parallel Input channel time, expressed in delay after PPFRi (0 to 125 µsec).
Po:
Parallel Output channel time, expressed in delay after PPFTi/o (0 to 125 µsec).
S/P:
Serial-to-Parallel data path.
Si:
Serial Input channel time, expressed in delay after F0i/o (0 to 125 µsec).
So:
Serial Output channel time, expressed in delay after F0i/o (0 to 125 µsec).
Transmission: The delay due to electronic circuits and physical media connecting the parallel ports of two MT90840s. (Assumed to be negligible in
TM3.)
Note 1: Exact P/S or S/P delay depends on relative positions of PPFRi and F0 +/- 120 nsec tolerance).
Note 2: Actual TM1 P/S and P/P delay depends on elastic position of PPFRi with respect to F0i (see ELD definition).
Note 3: Bypass delay in TM2: PPFT and PDo ch.0 are co-incident with PDi ch.235 at 19.44 MHz, ch.199 at 16 MHz, and ch.80 at 6.48 MHz. (TCP
= 1 delays PDo ch.0 an extra half clock-cycle in TM2).
Note 4: “Round-trip” delay from/to serial ports with the same F0 is always an integral number of frames (plus switching: So - Si).
Per-channel Control Outputs on the Parallel Port
The MT90840 provides four control outputs (CTo0-CTo3) which are synchronized to the parallel port output timing.
Each of the CTo output pins is controlled by the CT0-3 bits of the TPCM High. (The CTo0 pin and bit are
programmed with the Output Enable data.) The contents of the CTo bit in each TPCM High location is output on the
corresponding CTo pin once every frame. See Figure 9. The control outputs can be used to control other devices,
such as buffers, to allow sharing of the parallel port data bus.
Per-channel Tri-state (Serial and Parallel)
The MT90840 provides per-channel tri-state of the output pins on both the serial and parallel port. The OE bit in
each address of the TPCM and RPCM determines if data will be driven during a particular time slot, or if the pin will
be placed in a high-impedance state during that time slot. The OE bit overrides all other per-channel control bits.
Per-channel Message Mode (Serial and Parallel)
The MT90840 provides per-channel message mode capability on both the serial and parallel port. The MC bit in
each address of the TPCM and RPCM determines if the Connection Memory Low byte is to be used as an address,
or as data to be output on the particular channel (message mode). When the MC bit is HIGH, the Connection
Memory Low byte is used as message data. As well as driving message data on the serial (RPCM) and parallel
(TPCM) ports, the MT90840 allows the CPU to read serial or parallel data channels from the TPDM or RPDM.
Applications for message mode include digital silence, proprietary signalling, and creating fixed 8 kHz framing
patterns.
21
Zarlink Semiconductor Inc.
MT90840
Data Sheet
Output Frame Boundary Established by PPFT
PPFT
PDo7-0
Byte Timing
CTo0-3
Outputs
Channel 2428
TPCM High, CTn bit
address 2428
Channel 2429
Channel 0
Channel 1
TPCM High, CTn bit
address 2429
TPCM High, CTn bit
address 0
TPCM High, CTn bit
address 1
Note: For applications at 16.384 and 6.48 Mbyte/s, only 2048 and 810 positions are usable, in the TPCM.
Figure 9 - Parallel Port Control Outputs, CTo0-3
Per-channel Direction Control on the Serial Port
The MT90840 provides the ability to use any nominal output serial channel as an input or as an output. The
direction of each output serial channel is controlled by the DC bit in the appropriate byte of the Receive Path
Connection Memory High (RPCM High). When DC is HIGH the matching channel is an output. The per-channel
direction control feature of the MT90840 can be activated in one two modes: balanced, or add/drop operation.
•
Balanced Operation (all serial data rates)
This mode is enabled when the FDC bit in the IMS Register is LOW. In this mode, each of the DC bits controls two
serial channels: the nominal output and the nominal input. If a channel on a nominal output serial stream (STo0-7)
is re-defined as an input, the same-number channel on the matching input stream (STi0-7) will be defined as an
output. For example, if channel 0 on STo7 is programmed as an input (DC=0), then channel 0 on STi7 is defined as
an output. Each DC-bit’s state controls the direction of a channel on the nominal output stream (DC is HIGH for
output), and inverse-sense controls a channel on the nominal input stream (DC is LOW for output). This is shown in
Figure 10.
•
Add/Drop Operation (2.048 Mbps only)
This mode is enabled when the FDC bit in the IMS Register is HIGH. In Add/Drop mode all channels on all 16 serial
streams can be individually controlled, so that up to 512 channels can be either transmitted or received. As an
example, if all DC bit locations of RPCM High are set HIGH, all 512 channels on STo0-7 and STi0-7 will be
configured as outputs. If all DC bits are LOW, then all 512 channels will be configured as inputs. In Add/Drop mode
all 512 serial channels are copied into the Transmit Path Data Memory, as inputs, regardless of the DC or OE bits.
This has the effect of a “copy-back” of all serial outputs.
For more details on per-channel control functions for the serial and parallel data ports, see the TPCM High and
RPCM High bits definition in the Register Description section.
DC=0 for STo 0 channel 1
STi0
O/P
0
1
2
3
I/P
.....
29
STo0
I/P
30
31
MT90840
0
1
2
3
.....
O/P
29
30
DC=1 for STo 0 channel 29
Figure 10 - Balanced Per-Channel Serial Direction Control as Determined by DC Bit
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Zarlink Semiconductor Inc.
31
MT90840
Data Sheet
Serial Data Memory Addressing
The serial port mode determines the number of channels per stream, the number of streams, and the directioncontrol operation. Therefore the way in which serial data is addressed in the internal memory space must change
with the serial port mode. Because of this, it is necessary to select the serial port mode (with DR1-0 and FDC in the
IMS register) before programming the Receive Path Connection Memory.
2.048 Mbps Balanced Mode
The 2.048 Mbps Balanced mode has 8 serial input and 8 serial output streams, and 32 channels per stream.
Therefore 3 bits are used to address the 8 streams, and 5 bits are used to address the 32 channels. Figure 11a
shows how the Transmit Path Data Memory is read in this mode, by the CPU, or by the Transmit Path Connection
Memory. Each of the 256 input channels is mapped to an address in the TPDM. CPU reads require the LSB (Least
Significant Bit) of the CAR Register, and the 7 LSBs of the address bus. The source-channel address-value written
in the TPCM requires 8 bits.
Figure 11b shows how the Receive Path Connection Memory is addressed by the CPU. Each of the 256 output
channels has a control-address in the RPCM. CPU accesses require the LSB of the CAR Register, and the 7 LSBs
of the address bus. When the DC bit for a specific output channel is LOW, that channel is output on the STi pin
rather than the STo pin, and the data at the STo pin is input to the TPDM. When the DC bit is HIGH, the output
channel appears at the normal STo pin.
Serial Input
Channel
TPDM
Address
STi0, Ch0
000H
STi0, Ch1
..
001H
STi7, Ch30
0FEH
STi7, Ch31
0FFH
CPU Port Addressing:
CAR
0
Address Bus
6 5 4 3 2 1 0
Stream
Channel
TPCM Contents:
4 3 2 1 0
7 6 5
Stream
Note: Only 256 memory
locations.
Channel
Bits 7:5 select one of 8 streams.
Bits 4:0 select one of 32 channels
per stream.
Figure 11a - 2.048 Mbps Balanced Mode TPDM Addressing
Serial Output
Channel
RPCM
Address
STo0, Ch0
000H
STo0, Ch1
001H
..
CPU Port Addressing:
CAR
0
STo7, Ch30
0FEH
STo7, Ch31
0FFH
Address Bus
6 5 4 3 2 1 0
Stream
Channel
Note: Only 256 memory locations.
Figure 11b - 2.048 Mbps Balanced Mode RPCM Addressing
23
Zarlink Semiconductor Inc.
MT90840
Data Sheet
2.048 Mbps Add/Drop Mode
The 2.048 Mbps Add/Drop mode has 16 serial input/output streams, and 32 channels per stream. Therefore 4 bits
are used to address the 16 streams, and 5 bits are used to address the 32 channels. Figure 12a shows how the
Transmit Path Data Memory is read in this mode. Each of the 512 possible input channels is mapped to an address
in the TPDM. CPU reads require the 2 LSBs of the CAR Register, and the 7 LSBs of the address bus. The sourcechannel address-value written in the TPCM requires 9 bits. In this mode the TPDM reads all 512 serial channels as
inputs. When a specific channel is driven by the MT90840 as an output, the output data is also copied back into the
TPDM.
Figure 12b shows how the Receive Path Connection Memory is addressed by the CPU in 2.048 Mbps Add/Drop
mode. Each of the 512 possible output channels has a control-address in the RPCM. CPU accesses require the 2
LSBs of the CAR Register, and the 7 LSBs of the address bus. When the DC bit or the OE bit at a specific controladdress is LOW, no data is driven out for that channel, and the input data at the pin is written to the TPDM.
TPDM
Address
Serial I/O
Channel
STi0, Ch0
000H
STi0, Ch1
..
001H
STi7, Ch30
0FEH
STi7, Ch31
0FFH
STo0 (STi8), Ch0
100H
STo0 (STi8), Ch1
..
101H
STo7 (STi15), Ch30
1FEH
STo7 (STi15), Ch31
1FFH
CPU Port Addressing:
CAR
Address Bus
1 0
6 5 4 3 2 1 0
Stream
Channel
TPCM Contents:
8 7 6 5
4 3 2 1 0
Stream
Channel
Bits 8:5 select one of 16 streams.
Bits 4:0 select one of 32 channels per
stream.
Figure 12a - 2.048 Mbps Add/Drop Mode TPDM Addressing
24
Zarlink Semiconductor Inc.
MT90840
Data Sheet
RPCM
Address
Serial Output
Channel
STo0, Ch0
000H
STo0, Ch1
001H
.
.
CPU Port Addressing:
CAR
Address Bus
6 5 4 3 2 1 0
1 0
STo7, Ch30
0FEH
STi7, Ch31
0FFH
STi0 (STo8), Ch0
100H
STi0 (STo8), Ch1
.
.
101H
STi7 (STo15), Ch30
1FEH
STi7 (STo15), Ch31
1FFH
Stream
Channel
Figure 12b - 2.048 Mbps Add/Drop Mode RPCM Addressing
4.096 Mbps Mode
The 4.096 Mbps mode has 8 input and 8 output streams, and 64 channels per stream. Therefore 3 bits are used to
address the 8 streams, and 6 bits are used to address the 64 channels. Figure 13a shows how the Transmit Path
Data Memory is read in this mode. Each of the 512 input channels is mapped to an address in the TPDM. CPU
reads require the 2 LSBs of the CAR Register, and the 7 LSBs of the address bus. The source-channel addressvalue written in the TPCM requires 9 bits.
Figure 13b shows how the Receive Path Connection Memory is addressed by the CPU in 4.096 Mbps mode. Each
of the 512 output channels has a control-address in the RPCM. CPU accesses require the 2 LSBs of the CAR
Register, and the 7 LSBs of the address bus. Per-channel direction control in this mode is the same as the
2.048 Mbps Balanced mode.
Serial Input
Channel
TPDM
Address
STi0, Ch0
000H
STi0, Ch1
..
001H
STi7, Ch62
1FEH
STi7, Ch63
1FFH
CPU Port Addressing:
CAR
Address Bus
1 0
6 5 4 3 2 1 0
Stream
Channel
TPCM Contents:
8 7 6
Stream
5 4 3 2 1 0
Channel
Bits 8:6 select one of 8 streams.
Bits 5:0 select one of 64 channels per
stream.
Figure 13a - 4.096 Mbps TPDM Addressing
25
Zarlink Semiconductor Inc.
MT90840
Serial Output
Channel
RPCM
Address
STo0, Ch0
000H
STo0, Ch1
001H
.
.
Data Sheet
CPU Port Addressing:
CAR
Address Bus
1 0
STo7, Ch62
1FEH
STo7, Ch63
1FFH
6 5 4 3 2 1 0
Stream
Channel
Figure 13b - 4.096 Mbps RPCM Addressing
8.192 Mbps Mode
The 8.192 Mbps mode has 4 input and 4 output streams, and 128 channels per stream. Therefore 2 bits are used to
address the 4 streams, and 7 bits are used to address the 128 channels. Figure 14a shows how the Transmit Path
Data Memory is read in this mode. Each of the 512 input channels is mapped to an address in the TPDM. CPU
reads require the 2 LSBs of the CAR Register, and the 7 LSBs of the address bus. The source-channel addressvalue written in the TPCM requires 9 bits.
Figure 14b shows how the Receive Path Connection Memory is addressed by the CPU in 8.192 Mbps mode. Each
of the 512 output channels has a control-address in the RPCM. CPU accesses require the 2 LSBs of the CAR
Register, and the 7 LSBs of the address bus. Per-channel direction control in this mode is the same as the 2.048
Mbps Balanced mode.
Serial Input
Channel
TPDM
Address
STi0, Ch0
000H
STi0, Ch1
001H
..
CPU Port Addressing:
CAR
1 0
STi3, Ch126
1FEH
STi4, Ch127
1FFH
Address Bus
6 5 4 3 2 1 0
Channel
Stream
TPCM Contents:
8 7
Stream
6 5 4 3 2 1 0
Channel
Bits 8:7 select one of 8 streams.
Bits 6:0 select one of 128 channels
per stream.
Figure 14a - 8.192 Mbps TPDM Addressing
26
Zarlink Semiconductor Inc.
MT90840
Data Sheet
RPCM
Address
Serial Output
Channel
STo0, Ch0
000H
STo0, Ch1
001H
.
.
CPU Port Addressing:
CAR
1 0
Address Bus
6 5 4 3 2 1 0
Stream
STo3, Ch126
1FEH
STo4, Ch127
1FFH
Channel
Figure 14b - 8.196 Mbps RPCM Addressing
Microprocessor Port
An 8-bit multiplexed parallel microprocessor port is provided on the MT90840 to allow an attached CPU to configure
and read internal registers and memories. The MT90840 CPU interface is compatible with Motorola, National and
Intel Multiplexed Bus CPUs and adapts itself to the appropriate bus-type control signal timing without any mode
selection.
The MT90840 CPU interface signals are AD0-7 (Data and Address), ALE/AS, DS/RD, R/W\WR, CS and DTA. The
parallel microprocessor interface provides the CPU with access to the internal configuration registers, and the
Connection and Data Memories for both the transmit and receive paths. Connection memories are read/write, Data
Memories are read only, and the control register senses are shown in Table 2.
Accesses from the microport to the Connection and Data Memories are multiplexed with accesses from the input
and output TDM ports. This can cause variable data acknowledge delays which are communicated to the CPU by
the DTA output signal. Note that if the parallel port clocks PCKR & PCKT or serial port clocks C4/8R1 & C4/8R2 are
not present during an internal memory access, the DTA output signal may be held HIGH until the clocks are applied
again.
For complete details on the Microprocessor Interface timing signals, refer to the AC Electrical Characteristics
section.
Address Mapping of the Internal Registers
The MT90840 provides internal registers which are used by the CPU to configure the device in the various
operation modes. The IMS, TIM, GPM and ALS Registers should be initialized by the CPU on every system powerup before any internal memory access is performed. In the MT90840, the AD7 address pin must be kept LOW
when addressing the internal registers, as depicted in Table 2.
When input address pin AD7 is HIGH, input address pins AD0-AD6 are used together with bits HA7-HA11 in the
Control Register to form a 12-bit address to access the MT90840 internal memory selected by the SEL2-SEL0 bits.
See Internal Memory Description for memory address mapping.
IRQ Interrupt Pin
The MT90840 provides the output pin IRQ (Interrupt Request) which is active HIGH and indicates the occurrence of
one or more error conditions in the MT90840 timing operations. The occurrences are indicated by bits PPCE,
RXPAA, TXPAA and FSA in the ALS Register.
Except for cases where the indications are masked by the MSK3-0 bits in the ALS Register, the occurrence of any
indication causes an IRQ interrupt to be generated to the CPU. When an interrupt is masked by MSK3-0 bits, the
IRQ output will not be activated. However, the interrupt indication will still be provided in the ALS bits.
27
Zarlink Semiconductor Inc.
MT90840
Data Sheet
To cause the IRQ output signal or the indication bits to return to LOW again, the CPU can write any value to the
ALS Register (normally the Mask bits are re-written to clear the IRQ pin).
A7
A3
A2
A1
A0
#
Type
LOCATION
Reset Value
(Hex)
0
0
0
0
0
0
R/W
IMS Register
60
0
0
0
0
1
1
R/W
Control Register
00
0
0
0
1
0
2
R/W
TIM Register
00
0
0
0
1
1
3
R/W
GPM Register
00
0
0
1
0
0
4
R/W
ALS Register
0X
0
0
1
0
1
5
R/W
Test (leave 00hx)
00
0
0
1
1
0
6
-
reserved
0
0
1
1
1
7
-
reserved
0
1
0
0
0
8
RO
Phase Status (Low byte)
XX
0
1
0
0
1
9
RO
Phase Status (High 3 bits)
0X
0
1
0
1
0
10
-
reserved
Table 2 - MT90840 Register Address Mapping
DTA Data Transfer Acknowledgment Pin
The DTA pin is driven LOW by internal logic, to indicate to the CPU that a data bus transfer is complete. When the
bus cycle ends, this pin drives HIGH and then switches to high-impedance. If a short, or a signal contention,
prevents the DTA pin from reaching a valid logic HIGH, it will continue to drive for approximately 15 nsec before
switching to high-impedance.
Accessing Internal Memories
The Data and Connection memories of the MT90840 are connected to the various TDM data ports, and
synchronized to the TDM clocks (PCKR, PCKT, and C4/8R1 or C4/8R2). Therefore all CPU accesses to the Data
and Connection memories are synchronized to, and dependent upon, the TDM clocks. The TDM clocks supplied to
the MT90840 must meet the requirements given in the AC Electrical Characteristics section for reliable operation of
both the data switch and the CPU port. Faulty clocks can result in data corruption at the TDM ports, or on CPU
accesses.
If there is no PCKR clock (PCKT in TM1), the CPU cannot access the Transmit Path Connection Memory. If there is
no C4/8 clock, the CPU cannot access the Transmit Path Data Memory, Receive Path Data Memory, or Receive
Path Connection Memory. If the PPFRi or F0 frame pulse is absent, but the other clocks are present, the MT90840
will free-run and allow normal CPU access. (In TM2 with the INTCLK bit asserted, or in TM3 or TM4, all clocks and
all CPU memory accesses are tied to the PCKR clock.)
CPU Memory Read Operation
To perform a read, the Control Register must first be written to specify the memory and page to be read. Then the
CPU can read the specified memory and page by latching an address into the MT90840, with address pin AD7
HIGH to indicate a memory access. When chip-select and read signals are asserted, data is transferred to the CPU
port on the next free TDM clock edge, and then the DTA pin is asserted to indicate that the CPU port data pins hold
valid read- data. Numerous reads within the same memory page can be performed without having to re-write the
Control Register. CPU reads of the Data and Connection memories must be multiplexed with the TDM port
accesses, resulting in the varying DTA response times given in the AC Electrical Characteristics section.
28
Zarlink Semiconductor Inc.
MT90840
Data Sheet
CPU Memory Write Operation (Write Pipeline)
CPU write access to the Connection Memories (TPCM and RPCM) must also be multiplexed with the TDM port
accesses. To allow faster CPU write operations, the MT90840 has a transparent single-byte write pipeline. CPU
write accesses are performed in the same manner as reads, with the Control Register programmed to specify the
memory and page. The DTA pin is asserted by the MT90840 to indicate that the CPU data has been latched into
the device. An isolated write operation will receive a register-speed DTA, as the data is latched into the transparent
write pipeline to await the next free TDM clock edge. A second write will not receive a DTA acknowledgment until
the first write has exited the internal write pipeline. The DTA response time on the second write is a function of the
memory chosen for the write currently in the pipeline, and is given in the AC Electrical Characteristics section.
DTA Operation and TDM Clocks
If the CPU tries to read a memory for which the necessary TDM clock is not present, the DTA pin will not be
asserted. If the CPU tries to write a memory for which the necessary TDM clock is not present, the DTA pin will be
asserted (as the data is stored in the write-pipeline) but the next CPU access will not see DTA asserted. No clocks
are necessary for register accesses (but if the write-pipeline is hung, the registers cannot be accessed). If the
MT90840 is hung due to a CPU read of a memory with a missing clock, the hang can be cleared by ending the read
access. If the MT90840 is hung due to a CPU write to a memory with a missing clock, the hang can be cleared by
applying a hardware RESET to the MT90840.
Detecting Clock Presence
After it is set, the BPE bit is cleared within 2 frames of the C4/8 clock (i.e. within 250 µsec). If this bit is cleared by
the MT90840, the CPU can deduce that the C4/8 clock is present. In TM3, in TM4, and in TM2 with INTCLK
asserted, C4/8 is internally generated from PCKR, and if the BPE bit is cleared by the MT90840, the CPU can
deduce that the PCKR clock is present.
Clock Quality and TM1 TPCM Access Integrity
In Timing Mode 1 the parallel transmit frame pulse PPFTo must be held in phase with the serial bus frame pulse
input (F0i). This is performed automatically by the MT90840 with an internal correction event, which moves the
PPFTo output. In normal TM1 operation the correction happens once on initialization, and does not happen again
as long as the C4/8 and PCKT clocks stay phase-locked.
If the clocks lose their phase lock, the MT90840 will assert an automatic correction, and set the TXPAA interrupt bit
high. The transmit parallel port data, the CTO control data and the TX frame pulse (PPFTo) will all jump phase due
to this correction, causing one errored TDM frame.
If a CPU write to the Transmit Path Connection Memory is occurring during the one PCKT clock cycle that clocks
the correction, there is a chance that the write data will go to address 0, rather than the intended address. To avoid
this it is necessary to keep clocks stable during TPCM programming in TM1 (including not using DIN while
programming). If there is some doubt about the quality of the clocks in a particular application, options include:
-1- Program the TPCM in TM2, or TM2 with internal clocks (INTCLK=1), where this clock correction does not occur.
-2- Monitor the TXPAA interrupt bit during TPCM programming, and check the intended address, and address 0, if
a TXPAA alarm occurs.
-4- Read/verify address 0 after a block of TPCM writes. If address 0 is corrupted, one of the writes occurred during
a clock correction.
Clock Quality and TM2 RPCM Access Integrity
In Timing Mode 2 the serial frame pulse F0o must be held in phase with the parallel port RX frame pulse (PPFRi).
This is performed automatically by the MT90840 with an internal correction event, which inverts the phase of the
SPCKo output. In normal operation the correction happens once on initialization, and does not happen again as
long as the C4/8 and PCKR clocks stay phase-locked.
29
Zarlink Semiconductor Inc.
MT90840
Data Sheet
If the clocks lose their phase lock, the MT90840 will assert an automatic correction, and set the RXPAA interrupt bit
high. The serial port data and the ST bus frame pulse (F0o) will jump phase due to this correction, causing one
errored TDM frame. The PPCE bit indicates a change in framing at the receive parallel port which may cause a
“cascade” correction at SPCKo.
If a CPU write to the Receive Path Connection Memory is occurring during the one 4.096 MHz clock cycle that
clocks the correction, there is a chance that the write data will go to Stream0-Channel0, or Stream1-Channel0,
rather than the intended address. To avoid this it is necessary to keep clocks stable during RPCM programming in
TM2 (including not using DIN while programming). If there is some doubt about the quality of the clocks in a
particular application, options include:
-1- Program RPCM in TM1, where this correction does not occur.
-2- Program RPCM in TM2 with Internal Clock mode, (INTCLK=1) where this correction does not occur.
-3- Monitor the RXPAA interrupt bit during RPCM programming, and check the ST0-Ch0 and ST1-Ch0 addresses if
an alarm occurs.
-4- Read/verify ST0-Ch0 and ST1-Ch0 after a block of RPCM writes. If either is corrupted, one of the writes
occurred during a clock correction.
Memory Block-Programming
The MT90840 allows the user to program one value into the entire Transmit Path Connect Memory High, or
Receive Path Connect Memory High, with a single register write. This feature allows the four most significant bits of
each byte in the TPCM High, or RPCM High, to be automatically programmed with the value of the 4 PBD bits of
the GPM register. This eases system initialization by allowing all channels to be placed in high-impedance, or all
channels to be placed in bypass. The procedure works as follows:
a) The SEL2-0 bits in the Control Register are used to select Block-Programming for either the TPCM High, or
the RPCM High blocks. It is also necessary to select the serial port mode (with DR1-0 and FDC in the IMS
register) before programming the RPCM.
b) The GPM Register is written. The CPU sets the Block-Programming Enable (BPE) bit to HIGH and the
Block-Programming Data (BPD7-4) bits to the desired value. This action causes the contents of the BPD74 bits to be loaded into the four most significant bits of all addresses in TPCM High, or RPCM High (as set
by the Control Register).
c)
The user waits 250 µsec (two frames) to allow the TPCM High (2430 positions) or RPCM High (512
positions) to be entirely loaded with the new pattern.
d) After 250 µsec, the user should check that the BPE bit is LOW, indicating that the Block Program completed
successfully. If the BPE bit does not return to LOW, the necessary TDM clock input may not be available.
The BPE bit can be written LOW to force an end to the Block Programming.
Procedures a, b, c, and d must be performed twice if both TPCM and RPCM have to be initialized.
Block-programming requires stable F0 and PPFRi framing to function properly. If the framing jumps during blockprogramming, a section of memory may be missed. RPCM block-programming is dependent on the C4/8 serial port
clock and F0 framing. TPCM block programming is dependent on the PCKT clock, and F0 framing (PCKR, PPFRi
and F0 in TM2). DIN should not be active during block programming.
If there is some doubt about the quality of the clocks in a particular application, block-programming options include:
-1- If a stable C4/8 serial port clock is not available, or if a stable F0i frame is not available, use TM2 with Internal
Clocks (INTCLK=1) to perform block-programming of RPCM.
-2- If stable PPFRi framing is not available in TM2, disable the external gate driving PPFRi and use free-running
framing to perform block-programming of TPCM (and/or Internal Clocks mode to block-program RPCM).
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Zarlink Semiconductor Inc.
MT90840
Data Sheet
The interrupt source bits can also be monitored during block-programming. If PPCE, or RXPAA (in TM2), or TXPAA
(in TM1), is asserted during block-programming, a framing error has occurred and the block-programming should
be repeated.
Timing Mode Initialization
On system power-up, the CPU should program the MT90840 IMS, GPM, and TIM registers to establish the data
rates, the Timing Mode (1,2,3,4), and the framing polarity of the device. The MT90840 will then adjust its internal
rate conversion and time interchange circuits to accommodate the different rates set at both data ports.
To perform the rate conversions between the serial and the parallel ports, the MT90840 provides a phase alignment
circuit, monitored by the RXPAA and TXPAA interrupt bits. In TM1 and in TM2 with external clocks (INTCLK=0) the
phase alignment circuit works automatically to maintain the relative phase of the serial and parallel ports. The DIN
bit in the GPM register works with this circuit by reducing the window, forcing the phase alignment circuit to center
the relative phases.
After the parallel and serial port reference clocks (PCKT/PCKR and C4/8R1/C4/8R2) are stable, the DIN bit in the
GPM Register can be set HIGH. The DIN bit will auto-reset itself after 8 frames, returning to LOW. (It can also be
written LOW by the CPU.) The DIN bit procedure is especially useful in TM2. In TM1 the DIN bit also centers the
phase relation, but the movement of the transmit parallel port timing during the 8 frames that DIN is asserted may
cause data or framing errors in connected devices. The RPCM and TPCM should not be written to by the CPU
while DIN is asserted.
JTAG Support
BOUNDARY -SCAN CELL(BSC)
BSC
BSC
BSC
BSC
CORE LOGIC
BSC
BSC
BSC
BSC
T
A
P
C
O
N
T
R
O
L
L
E
R
TEST DATA IN (TDI)
TEST CLOCK (TCK)
TEST MODE
SELECT (TMS)
TEST DATA OUT (TDO)
Figure 15 - A Typical Boundary-Scan IC
The MT90840 boundary-scan circuitry functions in accordance with IEEE Std 1149.1a (often referred to as JTAG
boundary-scan). The standard specifies a design-for-testability technique called Boundary-Scan Test (BST). A
boundary-scan IC has a shift-register stage or ‘Boundary-Scan Cell’ (BSC) in between the core logic and the I/O
buffers adjacent to each I/O pin. The boundary-scan cellscan control and observe what happens at each I/O pin of
the IC. The operation of the boundary-scan circuitry is controlled by a Test Access Port (TAP) Controller.
Test Access Port (TAP)
The Test Access Port (TAP) has five signals and provides access to the test logic defined by the JTAG standard.
The TAP has the following connections:
•
Test Clock Input (TCK)
TCK provides the clock for the test logic. TCK is independent of the MT90840 functional clocks; this permits serial
shifting of test data along the Boundary-Scan chain concurrent with the normal operation of the MT90840.
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Zarlink Semiconductor Inc.
MT90840
•
Data Sheet
Test Mode Select Input (TMS)
The signal at TMS selects the operational mode of the TAP Controller. The TMS signals are sampled on the rising
edge of TCK. This pin is pulled high internally when not driven.
•
The Test Data Input (TDI)
Serial instructions and test-data are shifted in at this pin. Serial information is passed to the instruction register, the
boundary scan (test) register, or the bypass register, depending on the present mode of the TAP controller. TDI is
sampled on the rising edge of TCK. This pin is pulled high internally when not driven.
•
The Test Data Output (TDO)
Serial data is shifted out on this pin. Depending on the present mode of the TAP controller, data will come from one
of: the instruction register, the boundary scan register or the bypass register. TDO is clocked out on the falling edge
of TCK. When no data is being shifted, the TDO driver is set to a high-impedance state.
•
TRST:(Test reset input)
Asynchronously initializes the TAP controller by putting it in the Test-Logic-Reset state. This pin is pulled high
internally when not driven.
One additional pin influences the boundary scan test operation:
•
IC: (Manufacturing test pin)
This pin is an IEEE 1149 compliance-enable pin, and must be connected to Vss for proper boundary scan operation
(and normal chip operation).
Boundary-Scan Instruction Register
In accordance with the IEEE 1149.1 standard, the MT90840 uses public instructions listed in Table 3 - “Instruction
Register”. The MT90840 JTAG Interface contains a two bit instruction register. Instructions are serially loaded into
the Instruction Register from the TDI pin when the TAP Controller is in its Shift-IR state. Subsequently, the
instructions are decoded to achieve two basic functions: to select the test data register that may operate while the
instruction is current and to define the serial test data register path that is used to shift data between TDI and TDO
during data register scanning.
I[0:1] Instruction
Description
[00]
EXTEST
Boundary-Scan
This instruction is specifically provided to allow board-level interconnect
Register selected, testing of opens, bridging errors etc.
Test enabled
When the EXTEST instruction is executed, the MT90840 core logic is
isolated from the I/O pins, and the state of the I/O pins is determined by
the boundary-scan register. I/O data for this instruction is pre-loaded into
the boundary-scan register with the SAMPLE/PRELOAD instruction.
[01]
[10]
SAMPLE/PR Boundary-Scan
Two functions can be performed by the use of this instruction. It allows a
ELOAD
Register selected, SAMPLE (‘snapshot’) of the normal operation of the MT90840 to be
Test disabled
taken for examination. And, prior to the selection of another test
operation, a PRELOAD can place data values into the latched parallel
outputs of the Boundary-Scan cells. During the execution of the
instruction, the on-chip logic operation is not hampered in any way.
[11]
BYPASS
Bypass Register
selected,
Test disabled
This instruction is used to BYPASS the MT90840 while performing
boundary-scan testing on other devices with scan registers in the same
serial register chain. The MT90840 is allowed to function normally. This
instruction is automatically loaded upon TRST, as specified in
IEEE1149.1
Table 3 - Boundary-Scan Instruction Register
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Zarlink Semiconductor Inc.
MT90840
Data Sheet
Test Data Registers
As specified in the IEEE 1149.1 Standard, the MT90840 JTAG interface contains two test data registers:
•
The Boundary Scan Register consists of a series of Boundary-Scan Cells arranged to form a scan path
around the boundary of the core logic of the MT90840.
•
The Bypass Register is a single stage shift-register that provides a one-bit path that minimizes the distance
for test data shifting from the MT90840’s TDI to its TDO.
The MT90840 Boundary-Scan register contains 107 bits. The suffix (‘in’, ‘out’, or ‘en’) indicates the nature and
direction of the BSC. Bit 1 in Table 4 is the first bit clocked out. All tristate enable bits are asserted HIGH (i.e. a logic
1 enables the corresponding group of output/bidirectional pins). Note that clocking all zeros into the scan path
register will set all outputs to tristate (outputs disabled).
Cells
Definition
Note
1
ppfri_in
2
pckt_in
3
pckr_in
4:11
pdi_in
12:14
ppft_en, ppft_out, ppft_in
15:22
pdo_out
23
pdo_en
enables
pdo
outputs
24:27
cto_out
always
enabled
28
c48r2_in
29:31
f0_en, f0_out, f0_in
32
c48r1_in
33:35
sti_en, sti_out,
sti_in
36:53
sti, sti, ... sti
54:56
sti_en, sti_out,
sti_in
57
res_in
58
irq_en
59
irq_out
60
dta_out
61
first bit
out
tied
HIGH
internally
‘pseudo’
opendrain
cs_in
Table 4 - Boundary-Scan Register
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Zarlink Semiconductor Inc.
MT90840
Cells
Data Sheet
Definition
Note
62
asale_in
63
dsrdb_in
pin: ds/rd
64
wrb_in
pin:
r/w\wr
65:66
ad_out, ad_in
67:78
ad, ad, ... ad
79:80
ad_out, ad_in
81
ad_en
82:84
sto_en, sto_out,
sto_in
85:102
sto, sto, ... sto
103:105
sto_en, sto_out,
sto_in
enables
ad
outputs
106:107
spcko_en, spcko_out
Table 4 - Boundary-Scan Register
Please visit our web site at www.semicon.Zarlink.com to download a BSDL file for the MT90840.
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Zarlink Semiconductor Inc.
MT90840
Data Sheet
Register Description
Interface Mode Selection Register (IMS) - READ/WRITE
DR1
DR1-0
PPS1
PPS0
ODE
0
0
FDC
7
6
5
4
3
2
1
0
Serial Port Data Rate Selection. Select one of three different data rates at the serial inputs and outputs of the MT90840.
DR1 DR0
0
0
0
1
1
0
1
1
PPS1-0
DR0
Data Rate
2.048 Mbps
4.096 Mbps
8.192 Mbps
reserved
Parallel Port Data Rate Selection. Select one of three different data rates for the parallel port of the MT90840.
PPS1
0
0
1
1
PPS0
0
1
0
1
Data Rate
reserved. Do not use.
6.480 Mbyte/s.
19.44 Mbyte/s.
16.384 Mbyte/s.
ODE
Output Drive Enable. When LOW, forces the MT90840 output-buffers on the serial and parallel data ports into the high
impedance state (STo0-STo7, STi0-STi7, and PDo0-7). If this output is HIGH, all channels have their output drive enable
controlled by the per-channel OE bits of Transmit Connection Memory High, or Receive Connection Memory High.
FDC
Full Direction Control. This bit should only be set HIGH at the 2.048 Mbps serial rate. When FDC is set HIGH, each time slot
on each of the 16 ST-BUS pins can be individually configured as input or output. Up to 512 serial channels can be “inserted”
onto the Transmit parallel port, or up to 512 parallel channels can be “dropped” to the serial port. Individual channel direction
is controlled by the DC bits in the RPCM High. When FDC is LOW, the number of input and output time slots are “balanced”,
and setting a nominal input to be an output causes the same-number output time slot on the same-number STo pin to become an
input. For applications at 4.096 and 8.192 Mbps, this bit should be LOW.
Note: Bits 1 & 2 must be set to 0 by the CPU.
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Zarlink Semiconductor Inc.
MT90840
Data Sheet
Timing Mode Register (TIM) - READ/WRITE
0
TM1-0
TM1
TM0
C4/8R
TCP
INTCLK SFDI
PFDI
7
6
5
4
3
2
1
0
Timing Mode control bits. Define the four different timing modes described in the Timing and Switching Control section.
0
0
1
1
0
1
0
1
Timing
Timing
Timing
Timing
Mode
Mode
Mode
Mode
1
2
3
4
C4/8R
C4/8R Input Reference Select. If set high, this bit enables the 4.096 or 8.192 MHz serial port reference clock to be taken from
input pin C4/8R1. If LOW, the reference is taken from input pin C4/8R2 (default).
TCP
Parallel Port Transmit Clock Polarity. To allow the MT90840 parallel port transmit clock to comply with different 155 Mbps
framer backplanes, TCP controls which edge of the clock is used to transmit data at the parallel port. (The clock is PCKT in
TM1 or PCKR in TM2, 3, & 4). The TCP bit allows the rising (TCP=LOW) or the falling (TCP=HIGH) edges of the transmit
clock to be selected.
INTCLK Internal 4.096 MHz Clock Divider. For use in TM2, in 19.44 or 16.384 MHz parallel-port applications. This bit controls the
operation of the internal clock divider driven by PCKR. When INTCLK is set HIGH the internal 4.096 MHz clock (and the
SPCKo output) are generated by dividing down the PCKR clock. When INTCLK is set LOW, the C4/8R bit controls the source
for the serial clock reference. In TM3 and TM4 the MT90840 automatically sets itself in the internal divider mode and the state
of INTCLK has no effect. In TM1 this bit is must be set LOW.
SFDI
Serial Frame Pulse Direction Control. Normally LOW, unless it is necessary to operate multiple parallel MT90840 devices in
Timing Mode 2. When set HIGH, the F0 line becomes an input and this MT90840 is synchronized to the timing of another
MT90840 generating the F0o, and using the same 4.096 or 8.192 MHz reference input. One MT90840 in TM2 with SFDI LOW
can control several MT80940s with SFDI HIGH. When SFDI is set HIGH, INTCLK is ignored, and SPFP in the GPM register
must be set to the expected F0i polarity.
PFDI
Parallel Frame Pulse Direction Control. Normally LOW, unless it is necessary to operate multiple parallel MT90840 devices in
Timing Mode 1. When set HIGH, the PPFT pin becomes an input and this MT90840 is synchronized to the timing of another
MT90840 generating the PPFTo. One MT90840 in TM1 with PFDI LOW can control several MT80940s with PFDI HIGH.
When PFDI is HIGH, PPFP in the GPM register must be set to the expected PPFTi polarity.
Note: Bit 7 must be set to 0 by the CPU.
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Zarlink Semiconductor Inc.
MT90840
Data Sheet
General Purpose Mode Register (GPM) - READ/WRITE
BPD7
BPD6
BPD5
BPD4
PPFP
DIN
SPFP
BPE
7
6
5
4
3
2
1
0
BPD7-4
Block-Programming Data bits 7-4. These bits carry the value to be loaded into the TPCM-High or RPCM-High memory when
the Memory Block-Programming feature is activated. When BPE is set HIGH, the contents of bits BPD7-4 are loaded into the
four most significant bits of TPCM-High or RPCM-High, and the four least significant bits of TPCM-High or RPCM-High are
zeroed.
PPFP
Parallel Port Frame pulse Polarity. Used to program the polarity of the PPFT frame pulse. If PPFP is set HIGH, the frame
boundaries at the Parallel Port output will occur when PPFT pulse signal is HIGH. If PPFP is set LOW, the PPFT output will
indicate frame boundaries with a LOW active pulse. The transmit edge for the generation of PPFT, as well as PDo and CTo, is
determined by TCP in the TIM Register.
DIN
Device Initialization. This bit is used in TM1 and TM2 to center the phase relation between the parallel port clocks and the
serial port clock. It can be set HIGH by the CPU after the serial and parallel port rates are written in the IMS Register, and the
input clocks are stable. If the MT90840 internal divider is used (INTCLK bit = HIGH), or if TM4 or TM3 is selected, this bit is
not used. This bit is automatically returned low after 8 frames, and clears all interrupt source bits in the ALS register as long as
it is HIGH. The Connect Memories should not be programmed while DIN is asserted.
SPFP
Serial Port Framing Polarity. In TM2 and TM3 this bit defines the format of the serial port frame pulse F0o, and the clock
SPCKo. If SPFP is HIGH, F0o is set as a positive pulse with GCI timing. If SPFP is LOW, F0o is set as a negative pulse with
ST-BUS timing. In TM2 with SFDI set HIGH, this bit specifies the expected F0i input polarity. In TM1, the F0i input polarity is
automatically detected, and this bit is ignored. See the interface timing specifications.
BPE
Block-Programming Enable. This bit activates the memory block-programming feature. It can be set high after the SEL0-2 bits
in the Control Register are set to select the memory to be programmed. The BPE and BPD7-4 bits in this register must be
defined in the same write operation. Once BPE is set HIGH, the user should wait at least 250 µs and then check BPE = LOW to
see that the operation completed successfully. This bit can also be written low to force the end of the block-program operation.
Note :
The CPU must maintain the required settings of the PPFP and SPFP bits when BPE is written. The DIN function and the BPE
function should not be used simultaneously.
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Zarlink Semiconductor Inc.
MT90840
Data Sheet
Alarm Status Register (ALS) - READ/WRITE
MSK3
MSK2
MSK1
MSK0
PPCE
7
6
5
4
3
RXPAA TXPAA
2
1
FSA
0
MSK3-0
Mask Alarm Bits 3-0. These bits mask the specific interrupt source bits. MSK3 masks PPCE, MSK2 masks RXPAA, etc. If
MSKn is set HIGH, the corresponding interrupt source is enabled, and the IRQ pin will respond to that interrupt source; if set
LOW, the corresponding interrupt source is masked. When masked, an interrupt source will not assert the IRQ pin, but will still
set the ALS register bit. On system power-up, all interrupts are masked. Writes to the ALS register clear the low nibble
(interrupt source bits) regardless of the data written.
PPCE
Parallel Port Frame Counter Error. Used in all timing modes. The PPCE bit goes HIGH whenever there is an incorrect number
of PCKR clock cycles between PPFRi frame sync signals on the Receive parallel port. The numbers of clock cycles expected
depends on the parallel port rate selected in the IMS Register (2430, 2048, or 810 clock cycles). The absence of PPFRi for one
or more frames will not cause an interrupt (allowing free-run operation), but the PPCE bit will go HIGH if PPFRi occurs
anywhere but on an expected frame boundary.
RXPAA
RX Phase Alignment Alarm. Used in TM2 operation, when INTCLK = 0. The RXPAA bit goes HIGH whenever the C4/8 input
reference goes out of phase relative to the parallel port clock (PCKR). A rising edge on the RXPAA bit indicates that the MT90840
has adjusted the position of F0o and SPCKo, and a data slip at the serial port has occurred. Note that a CPU write to the RPCM
memory as RXPAA goes HIGH (in TM2) may be corrupted. In TM2 with SFDI = 1, a rising edge on the RXPAA bit indicates that
the F0i input is out of phase with PPFRi, implying a failure in the timing supplied by the controlling (TM2 with SFDI = 0)
MT90840. When not in TM2 the RXPAA bit may be continuously asserted, and therefore should be masked by setting MSK2 LOW,
and ignored.
TXPAA
TX Phase Alignment Alarm. Used in TM1 operation. The TXPAA bit goes HIGH whenever the PCKT clock input goes out of
phase relative to the C4/8 clock. A rising edge on the TXPAA bit indicates that the MT90840 has adjusted the position of
PPFTo, and a data slip at the TX parallel port output has occurred. Note that a CPU write to the TPCM memory as TXPAA goes
HIGH (in TM1) may be corrupted. In TM1 with PFDI = 1, a rising edge on the TXPAA bit indicates that the PPFTi input is out of
phase with F0i, implying a failure in the timing supplied by the controlling (TM1 with PFDI=0) MT90840.
FSA
Frame Slip on Elastic Buffer. Used in TM1 operation. The FSA bit goes HIGH when either an overflow or underun condition on
the Receive parallel port’s elastic buffer has been detected. A rising edge on the FSA bit indicates that a frame of data from the
RX parallel port has been dropped, or repeated. In TM2, TM3, and TM4 the user should mask this bit by setting MSK0 LOW.
Note:
The interrupt source bits are latched, and remain high until cleared by the CPU. The interrupt source bits (ALS low nibble) are
cleared by writing the mask bits (ALS high nibble), regardless of the data written.
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Zarlink Semiconductor Inc.
MT90840
Data Sheet
Control Register (CR) - READ/WRITE
SEL2
SEL1
7
6
SEL0
HA11
HA10
5
4
3
HA9
2
HA8
HA7
1
0
This register selects which 128 byte page of which internal memory will be accessed by the CPU when the address bit AD is high.
(When address bit AD is low, the control registers are accessed.)
SEL2-0
Memory Select bits. Used by the CPU to select the internal memories of the MT90840 for read or write operations. SEL2-0 bits
have to be written before any READ/WRITE operation is performed on the internal memories.
SEL2
SEL1
SEL0
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
HA11-7
Memory Selected for RD/WR operation
Receive Path Connection Memory Low (RPCM Low)
Receive Path Connection Memory High (RPCM High)
Receive Path Data Memory (RPDM)
Enable Memory Block-Programming feature for RPCM High
Transmit Path Connection Memory Low (TPCM Low)
Transmit Path Connection Memory High (TPCM High)
Transmit Path Data Memory (TPDM)
Enable Memory Block-Programming feature for TPCM High
High Address Bits 11-7. These bits select which 128 byte page of the selected memory (see SEL2-0 bits) will be accessed by
the CPU. Used along with AD0-AD6 input lines to address the MT90840 internal memories when the address bit AD is
high. See RPCM, TPCM, RPDM and TPDM Address Mapping section for more details.
To address serial time slots in TPDM or RPCM:
Number of Serial Port Input
and Output Streams
HA bits and input address lines, or
TPCM address bits, used to select ST
stream.
HA bits and input address lines, or TPCM
address bits, used to select the time slot.
2 Mbps Balanced
8i x 8o (256 channels)
HA7 + AD6-AD5 / AB7-AB5
AD4-AD0 / AB4-AB0 (32 time slots)
2 Mbps Add/Drop
16 i/o (512 channels)
HA8-HA7 + AD6-AD5 / AB8-AB5
AD4-AD0 / AB4-AB0 (32 time slots)
4 Mbps
8i x 8o (512 channels)
HA8-HA7 + AD6 / AB8-AB6
AD5-AD0 / AB5-AB0 (64 time slots)
8 Mbps
4i x 4o (512 channels)
HA8-HA7 / AB8-AB7
AD6-AD0 / AB6-AB0 (128 time slots)
Serial Port
Data Rate
To address parallel time slots in RPDM or TPCM:
Parallel Port Data
Rate
Number of Channels
HA bits and input address lines used to
select channel in TPCM.
RPCM address bits used to select channel.
19.44 Mbyte/s
2430
HA11-HA7 + AD6-AD0
AB11-AB0
16.384 Mbyte/s
2048
HA10-HA7 + AD6-AD0
AB10-AB0
6.480 Mbyte/s
810
HA9-HA7 + AD6-AD0
AB9-AB0
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Zarlink Semiconductor Inc.
MT90840
Data Sheet
Phase Status Registers (PSD) - READ Only
PSD7
PSD10-0
PSD6
PSD5
PSD4
PSD3
PSD2
PSD1
7
6
5
4
3
2
1
0
0
0
0
0
PSD10
PSD9
7
6
5
4
3
2
1
PSD0
Register Address 8 (Low Byte)
0
PSD8
Register Address 9 (High 3-bits)
0
Phase Status Data 10-0. The PSD bits represent the phase status of the serial port, as sampled at every second PPFRi frame
(every 250 µsec). PSD0 is the phase of the internal 4.096 MHz clock, PSD1-9 count the cycles of the 4.096 MHz within a
frame, and PSD10 toggles each frame (even/odd frame bit). The PSD bits enable the CPU to monitor the relative phases of the
Receive parallel port and the serial port. This is especially useful in TM1, where the PSD bits might be used by the CPU to
monitor a PLL control loop, since the elastic buffer in the Receive parallel port allows great variation in phase. These registers
should be read twice in succession, in case the CPU access occurs close to the sampling edge.
Internal Memory Description
Transmit Path Connection Memory High (TPCM High) - This is an 8-bit x 2430-position memory.
OE/
CTo0
7
PPBY
MC
CTo1
CTo2/
AB11
CTo3/
AB10
AB9
AB8
6
5
4
3
2
1
0
(TX Path CM High)
OE/CTo0 Output Enable. Provides per channel tristate control on the parallel port side. It controls the MT90840 parallel output drivers to
disable (tristate, when LOW) or enable (when HIGH) the transmission of data from the device. The contents of this bit will also
be clocked out on the CTo0 output pin at the parallel port rate.
PPBY
Parallel Port Bypass Enable. Indicates that the parallel output channel is going to contain bypassed (PPBY=HIGH) data from
the Receive parallel port of the MT90840. The channels that are not bypassed (PPBY=LOW) can be used for switching of data
from the serial port side, or for message-mode data. The use of this bit is only allowed in Timing Modes 1 and 2. The PPBY bit
is overridden by MC set HIGH.
MC
Message Channel. The message channel contents are programmed by the CPU into the TP Connection Memory Low. If MC=1
the contents of the corresponding location of TPCM Low are output on the corresponding channel at the Transmit parallel port.
If MC=LOW, the contents of the programmed location in TPCM Low act as an address for the Data Memory, and so determine
the source channel for this output channel. Depending on the timing mode selected, the source of the connection can be an input
channel from either serial (TM1, 2, or 3) or parallel (TM4) data ports. This bit overrides PPBY if both are set HIGH.
CTo1-3
External Control Lines 1-3. These three bits are used by the CPU to program the three external control pins CTo1-3. Like
OE/CTo0, the contents of these lines will be transmitted to pins CTo1-3 at the parallel port rate. Note: CTo2 and CTo3 cannot
be used in Timing Mode 4.
AB8-11
Source Channel Address Bits 8-11. These bits are used along with bits AB0-7 in TPCM Low to select the source channel for
this output channel. In all timing modes except TM4, only bit AB8 is used, along with bits AB0-7 in TPCM Low, to select one
of 512 serial source channels from the serial port side to be transmitted on this output channel.
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Zarlink Semiconductor Inc.
MT90840
Data Sheet
Transmit Path Connection Memory Low (TPCM Low) - This is an 8-bit x 2430-position memory.
AB7
7
AB7-0
AB6
6
AB5
5
AB4
AB3
AB2
AB1
AB0
4
3
2
1
0
(TX Path CM Low)
Source Channel Address Bits. In Timing Modes 1, 2, and 3, these 8 bits are used along with bit AB8 in the TPCM High to select
up to 512 serial source channels from the serial port side to be connected to any 512 (out of 2430) output channels available on
the parallel port side. See table for details.
In Timing Mode 4, these 8 bits are used along with bits AB8-11 in the TPCM High memory to select up to 2430 source channels
from the parallel port input to be connected to any of the 2430 channels available on the parallel port output side.
If message mode is selected at TPCM High bits, the contents of the AB0-7 bits in the TPCM Low locations are transmitted to
the corresponding channels at the PDo0-7 lines until the mode is changed by the CPU.
USE OF THE TPCM HIGH AND LOW ADDRESS BITS WHEN SELECTING SOURCE SERIAL-PORT CHANNELS (TM1, TM2 and TM3)
SERIAL STREAM and CHANNEL ALLOCATION
SOURCE STREAM ADDRESSING
SOURCE CHANNEL ADDRESSING
2 Mbps
16 i/o (512 channels)
AB5,AB6,AB7,AB8 (up to 16 streams)
AB0 to AB4 used to select up to 32 channels per
stream
4 Mbps
8i x 8o (512 channels)
AB6, AB7, AB8 used to select up to 8 streams
AB0 to AB5 used to select up to 64 channels per
stream
8 Mbps
4i x 4o (512 channels)
AB7, AB8 used to select up to 4 streams
AB0 to AB6 used to select up to 128
channels per stream
SOURCE CHANNEL ADDRESSING IN TM4
6.48 Mbyte/s
AB0-AB9 (one of 810 input channels)
16.384 Mbyte/s
AB0 - AB10 (one of 2048 input channels)
19.44 Mbyte/s
AB0 - AB11 (one of 2430 input channels)
41
Zarlink Semiconductor Inc.
MT90840
Data Sheet
Receive Path Connection Memory High (RPCM High) - This is a 7-bit x 512-position memory.
Used only in TM1, 2, & 3.
7
MC
DC
OE
AB11
6
5
4
3
AB10
2
AB9
AB8
1
0
(RX Path CM High)
MC
Message Channel: The message channel contents are provided by the CPU in bits AB0-7 in the Rx Path Connection Memory
Low. If MC is HIGH, the contents of the corresponding location of RPCM Low are output on this serial port channel. If MC is
LOW, the contents of the corresponding location in RPCM Low act as an address for the Rx Path Data Memory and so
determine the source of the connection (input channels from the PDi0-7 port).
DC
Direction Control: DC set HIGH indicates this channel is an output. DC set LOW indicates this channel is an input. The
operation of this bit is modified by the state of FDC in the IMS Register.
When FDC = LOW (2.048, 4.096 or 8.192 Mbps) the 512 DC bits (256 at 2.048) each define the direction of a pair of pins for
each channel. When DC is set LOW the associated channel on the STo pin becomes an input, and the corresponding channel on
the same-number STi pin is automatically used as the output for this time slot. When DC is set HIGH, STo is the output, and STi
is the input for this time slot (default).
When FDC = HIGH (2.048 Mbps), the 512 DC bits can be used to control the direction of each individual 64 kbps time slot
present on the 16 serial I/O lines on a non-symmetrical basis; i.e. all 512 channels can be configured as outputs or inputs or any
mixed combination. If DC is LOW, this serial port channel is defined as input. If DC is HIGH, this channel is defined as output.
Note that the CPU still has to set OE to enable the output buffers on each channel defined as an output.
OE
Output Enable. Per-channel tristate control for each channel on the serial port side. If FDC is HIGH, the 512 OE bits enable the
output for each of the 512 ST channels, unless the channel is defined as an input by the DC bit. In 4.096 and 8.192 Mbps modes,
the OE bit enables the output buffer either on a STo pin, or an STi pin, as defined by the accompanying DC bit.
AB8-11
Source Channel Address. These 4 bits are used along with AB0-7 to select any of the 2430 parallel incoming channels from the
parallel port and determine the switch connection to the 512 possible destination channels on the serial port.
Receive Path Connection Memory Low (RPCM Low) - This is an 8-bit x 512-position memory.
Used only in TM1, 2 &3.
AB0-7
AB7
AB6
7
6
AB5
5
AB4
AB3
4
3
AB2
2
AB1
1
AB0
(RX Path CM Low)
0
Source Channel Address. In switching mode (MC=LOW), these 8 bits are used along with AB8-11 to select one of the 2430
incoming channels from the parallel port. In message mode (MC=HIGH), these 8 bits are programmed by the CPU with the
message patterns desired on the corresponding serial output channel.
Applications
Distributed Isochronous Network
Low latency isochronous backbones provide for the deployment of systems that require cost effective
implementation, high bandwidth, predictable data transfer delays and direct synchronization with the wide area
network.
Some applications in Computer Telephony Integration (CTI) require a large amount of bandwidth to be transported
between multiple chassis within the same location, or between separate locations. The MT90840 is ideal for
implementing physically distributed transport and switching systems for multi-chassis or inter-shelf
communications.
The MT90840 bridges existing Zarlink ST-BUS components into a new networking environment where mixed data,
voice and video signals can be time-interchanged or multiplexed from serial PCM streams onto serial high-speed
time-division- multiplex (TDM) isochronous backbones operating at SONET rates such as 51 (STS-1) or 155 Mbps
(STS-3).
42
Zarlink Semiconductor Inc.
MT90840
Data Sheet
Today, transmission links operating at SONET rates utilize serial-to-parallel and parallel-to-serial converters (or
framers) which perform embedded framing functions and give the user access to the payload of the high speed
frame. The MT90840 provides an 8-bit bidirectional parallel data port which directly interfaces to a high-speed
framer parallel data interface, allowing designers to build distributed networking systems with interconnection
speeds up to 155 Mbps. Figure 16 shows an example of a distributed networking application in a CTI system.
The MT90840's clock synchronization and reference options allow many applications and topologies when
isochronous TDM backbones are required. Two major clock synchronization schemes provided by the MT90840
allow the serial port interface (ST-BUS) to provide the master clock and frame reference signals for the distributed
high speed backbone (master operation) or to derive the entire ST-BUS clock and frame reference signals from the
high speed backbone (slave operation). This type of synchronization scheme may be used in applications such as
the proposed MVIP multi-chassis level 3 interface (MC-3 system) utilizing point-to-point or point-to-multipoint
switching connections.
When the MT90840 operates in a ring application, the Parallel Data Bypass mode is provided to allow all or part of
the received input parallel data to be bypassed to the output parallel port feeding the ring back with the data which
is not destined for the local station. The data destined for the local station can be dropped through CPU
programming. In this mode, the CPU has full control of the outgoing bandwidth (from the serial interface to the high
speed link) so that it does not contend with the bypassed data.
CTI Server
24/30B+D
ST-BUS
Switching
BUS
e.g.; MVIP
MT90810
FMIC
PSTN
CTI
SERVER
Call
Processing
155 Mbps
Framing &
MT90840
MT90810
FMIC
MT8977/9079
T1 & E1 I/F
Optics
ST-BUS
Up to 2400 TDM
channels of user data
MT896x
Filter/Codec
Filter/Codec
ST-BUS
MT8985/6
EDX
MT8930 / 71
(2B+D) I/F
ISO Ethernet
MUX
CTI
SERVER
LAN ADAPTER CARD
Interchassis Signalling
(e.g. Zarlink’s Connection
Master Software)
Figure 16 - CTI Distributed Architecture Implemented with the MT90840
43
Zarlink Semiconductor Inc.
MT90840
Data Sheet
Absolute Maximum Ratings*
Parameter
Symbol
Min.
Max.
Units
VDD
0
6
V
VSS-0.3
VDD+0.3
V
40
mA
+125
°C
2
W
1
Supply Voltage
2
Voltage on any I/O pin
VI
3
Continuous Current at Digital Outputs
IO
4
Storage Temperature
TS
5
Package Power Dissipation
PD
-65
* Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied.
Recommended Operating Conditions - Voltages are with respect to ground (VSS) unless otherwise stated.
Characteristics
Sym.
Min.
1
Operating Temperature
TOP
-40
2
Positive Supply
VDD
4.75
3
Input Voltage
VI
0
Typ.
5.0
Max.
Units
+85
°C
5.25
V
VDD
V
Test Conditions
DC Electrical Characteristics - Voltages are with respect to ground (VSS) unless otherwise stated.
Characteristics
Sym.
Supply Current at
19.44 Mbyte/sec & 4 Mbps
IDD
Input High Voltage
VIH
Input Low Voltage
VIL
Input High-Going Threshold
VT+
Input Low-Going Threshold
VT-
6
Input Leakage (I/O pins)
IIL
7
Input Pin Capacitance
CI
8
Output High Voltage
VOH
9
Output Low Voltage
VOL
Output High Current
(sourcing at VOH)
or
Output Low Current
(sinking at VOL)
IOH
or
IOL
1
2
3
4
5
10
11
12
I
N
P
U
T
S
O
U
T
P
U
T
S
Min.
Typ.‡
Max.
Units
100
160
mA
2.0
2.8
0.9
Test Conditions/Pins
Outputs unloaded
V
TTL inputs (most pins)
0.8
V
TTL inputs (most pins)
4.2
V
Schmitt inputs
V
Schmitt inputs
50
µA
VI between VSS and VDD
10
pF
1.8
2.4
0.4
V
Sourcing IOH
V
Sinking IOL
9
mA
Pins: STi4-7, STo4-7
16
mA
TDO, RPA, DTA, AD7-0,
F0, SPCKo, STi0-3, STo03
28
mA
PDo0-7, CTo3-0, PPFTo
VO between VSS and VDD.
Pins: PDo0-7, CTo3-0
High Impedance Leakage
IOZ
5
µA
Output Pin Capacitance
CO
10
pF
‡ Typical figures are at 25°C and are for design aid only: not guaranteed and not subject to production testing.
44
Zarlink Semiconductor Inc.
MT90840
Data Sheet
AC Electrical Characteristics - Voltages are with respect to ground (VSS) unless otherwise stated.
Characteristics
1
C4/8 Input - Clock Period:
4.096 MHz (2.048 & 4.096 Mbps)
8.192 MHz (8.192 Mbps)
Sym.
tclk
SPCKo Output - Clock Period from
internal divider (2.048 & 4.096 Mbps)
SPCKo Output - Clock Period
generated from external C4/8 reference
(2.048 and 4.096 Mbps)
2
3
C4/8 Input Clock Width HIGH
4.096 MHz (2.048 & 4.096 Mbps)
8.192 MHz (8.192 Mbps)
tclkh
Min.
Typ.‡
200
100
244
122
ns
19.44 MHz 60/40% dutycycle clock at PCKR
241
245
ns
C4/8R1 input with 244 ns
cycle
C4/8R1 or C4/8R2
85
50
110
122
61
CLK rise/fall time
tt
5
F0 output delay from SPCKo
(TM2 & TM3, 2.048 and 4.096 Mbps)
tdf
122
61
7
8
tfrs
F0i Hold Time from C4/8 input edge
TM1
TM2 with SFDI =1
tfrh
F0i Input Frame Pulse Width
2.048, 4.096, 8.192 Mbps
tfrw
19.44 MHz 60/40% dutycycle clock at PCKR
ns
C4/8R1 input with min.
115 ns semi-cycle
ns
ns
135
5
ns
PCKR with 60/40% duty
cycle
ns
C4/8R1 input with
minimum 115 ns halfcycle
ns
32
51
ns
CL=30pF
CL=150pF
30
46
ns
CL=30pF
CL=150pF
0
28
ns
ns
C4/8 falling edge
8
0
ns
ns
C4/8 falling edge
C4/8 rising or falling
35
ns
F0 output delay from C4/8 input
(TM2 & TM3, 8.192 Mbps)
F0i Setup Time from C4/8 input edge
TM1
TM2 with SFDI =1
ns
C4/8R1 or C4/8R2
85
50
110
4
6
ns
ns
135
101
SPCKo Output - Clock Width LOW
generated from external C4/8 reference
(2.048 and 4.096 Mbps)
ns
ns
259
SPCKo Output - Clock Width HIGH
generated from external C4/8 reference
(2.048 and 4.096 Mbps)
SPCKo Output - Clock Width LOW from
internal divider (2.048 & 4.096 Mbps)
Test Conditions
224
101
tclkl
Units
C4/8R1 or C4/8R2
SPCKo Output - Clock Width HIGH
from internal divider (2.048 & 4.096
Mbps)
C4/8 Input - Clock Width LOW
4.096 MHz (2.048 & 4.096 Mbps)
8.192 MHz (8.192 Mbps)
Max.
45
Zarlink Semiconductor Inc.
MT90840
Data Sheet
AC Electrical Characteristics - Voltages are with respect to ground (VSS) unless otherwise stated.
Characteristics
9
Sym.
Units
38
50
26
ns
ns
ns
38
50
26
ns
ns
ns
40
64
ns
ns
CL=30pF
CL=150pF
STo Output Delay from 4.096 MHz C4/8
input (TM1)
52
72
ns
ns
CL=30pF
CL=150pF
STo 8.192 Mbps Output Delay from
C4/8 input (TM1, 2 & 3; STi/o0-3)
28
43
ns
ns
CL=30pF
CL=150pF
28
41
ns
SPCKo CL=30pF
SPCKo CL=150pF
STi Input Setup Time from C4/8 input
edge in TM1 (2.048 and 4.096 Mbps)
0
ns
STi Input Setup Time from C4/8 input
edge at 8.192 Mbps (STi/o0-3)
0
ns
9
2
ns
20
ns
taz
10 STo Delay from High-Z to Active
2.048 and 4.096 Mbps (TM2 &TM3)
2.048 and 4.096 Mbps (TM1)
8.192 Mbps (STio0-3)
tza
11 STo Output Delay from SPCKo
(TM2 & TM3, 2.048 and 4.096 Mbps)
tsod
12 STi Input Setup Time from SPCKo
output edge (2.048 and 4.096 Mbps)
tstis
13 STi Input Hold Time from SPCKo output
edge (2.048 and 4.096 Mbps)
tstih
STi Input Hold Time from C4/8 input
edge in TM1 (2.048 and 4.096 Mbps)
‡
Typ.‡
Max.
STo Delay - Active to High-Z,
2.048 and 4.096 Mbps (TM2 &TM3)
2.048 and 4.096 Mbps (TM1)
8.192 Mbps (STio0-3)
Min.
Test Conditions
CL=30pF, RL=1K
CL=30pF, RL=1K
TM1 and TM2,
STi0-3, STo0-3
SPCKo CL=30pF
SPCKo CL=150pF
TM1 and TM2,
STi Input Hold Time from C4/8 input
STi0-3, STo0-3
13
ns
edge at 8.192 Mbps
Typical figures are at 25°C and are for design aid only: not guaranteed and not subject to production testing.
VDD
Test Point
RL
Output
Pin
S1
S2
CL
VSS
VSS
Figure 17 - Output Test Load
46
Zarlink Semiconductor Inc.
S1 is open circuit except
when testing output levels
or high impedance states.
S2 is switched to VDD or
VSS when testing output
levels or high impedance
states.
MT90840
Data Sheet
tfrw
Foi input
(8 kHz)
tfrh
tfrs
tclk
tT
tclkh
tclkl
C4/8R1
(4.096 MHz)
STi0-7
tstis
bit 0, ch. 31
tstih
bit 7, ch. 0
tsod
STo0-7
bit 0, ch. 31
bit 7, ch. 0
Serial Port with Negative Polarity F0 (ST-BUS)
tclk
tt
tclkh
tclkl
C4/8R1
(4.096 MHz)
tsod
STo0-7
bit 0, ch. 31
bit 6, ch. 0
bit 7, ch. 0
tstis
STi0-7
bit 7, ch. 0
bit 0, ch. 31
tfrs
F0i input
(8 kHz)
tstih
tfrh
tfrw
Serial Port with Positive Polarity F0 (GCI)
Note: In TM2 with SFDI=1, C4/8R1 may have reversed polarity from that shown.
Figure 18 - Serial Port Timing for 2.048 Mbps Operation - TM2 (SFDi = 1) and TM1
47
Zarlink Semiconductor Inc.
MT90840
Data Sheet
F0ooutput
(8 kHz)
tdf
tdf
tclk
tT
tclkh
tclkl
SPCKo
(4.096 MHz)
tstis
tstih
STi0-7
bit 0, ch. 31
bit 7, ch. 0
tsod
STo0-7
bit 0, ch. 31
bit 7, ch. 0
Serial Port with Negative Polarity F0 (ST-BUS)
tclk
tt
tclkh
tclkl
SPCKo
(4.096 MHz)
tsod
STo0-7
bit 6, ch. 0
bit 7, ch. 0
bit 0, ch. 31
tstis
STi0-7
tstih
bit 7, ch.0
bit 0, ch.31
tdf
tdf
F0o output
(8 kHz)
Serial Port with Positive Polarity F0 (GCI)
Figure 19 - Serial Port Timing for 2.048 Mbps - TM2 (SFDi = 0) and TM3
48
Zarlink Semiconductor Inc.
MT90840
Data Sheet
tclk
C4/8R1
(4.096 MHz)
tclkh
tt
tclkl
tsod
STo0-7
bit 7, ch. 0
bit 0, ch. 63
tstis
STi0-7
bit 6, ch. 0
tstih
bit 7, ch. 0
tfrs
F0i input
(8 kHz)
tfrh
tfrw
Serial Port with Negative Polarity F0 (ST-BUS)
tclk
tclkh
tclkl
tt
C4/8R1
(4.096 MHz)
tsod
STo0-7
bit 7, ch. 0
bit 0, ch. 63
tstis
STi0-7
tstih
bit 7, ch. 0
tfrs
F0i input
(8 kHz)
bit 6, ch. 0
tfrh
tfrw
Serial Port with Positive Polarity F0 (GCI)
Note: In TM2 with SFDI=1, C4/8R1 may have reversed polarity from that shown.
Figure 20 - Serial Port Timing for 4.096 Mbps Operation - TM2 (SFDi = 1) and TM1
49
Zarlink Semiconductor Inc.
MT90840
Data Sheet
tclk
tclkh
tt
tclkl
SPCKo
(4.096 MHz)
tsod
STo0-7
bit 7, ch. 0
bit 0, ch. 63
tstis
bit 6, ch. 0
tstih
STi0-7
bit 7, ch. 0
tdf
tdf
F0o output
(8 kHz)
F0 Frame Sync with Negative Polarity (SPFP = 0)
tclk
tclkh
tclkl
tt
SPCKo
(4.096 MHz)
tsod
STo0-7
bit 7, ch. 0
bit 0, ch. 63
tstis
STi0-7
bit 6, ch. 0
tstih
bit7, ch. 0
tdf
tdf
F0o output
(8 kHz)
F0 Frame Sync with Positive Polarity (SPFP = 1)
Figure 21 - Serial Port Timing for 4.096 Mbps Operation - TM2 (SFDi = 0) and TM3
50
Zarlink Semiconductor Inc.
MT90840
Data Sheet
tclk
tclkh
tt
tclkl
C4/8R1
(8.192 MHz)
tsod
STo0-7
bit 7, ch. 0
bit 0, ch.127
tstis
bit 6, ch. 0
tstih
STi0-7
bit 7
tfrh
tfrs
F0i input
(8 kHz)
tfrw
Note: Polarity of F0i is automatically detected in TM1.
Expected polarity of F0i in TM2 (SFDI=1) must be programmed with SPFP bit in GPM register.
Figure 22 - Serial Port Timing for 8.192 Mbps - TM1 and TM2 (SFDi = 1)
C4/8
(GCI)
C4/8
(ST-BUS)
tza
STo0-7
Hi-Z
Valid Data
taz
STo0-7
Valid Data
Hi-Z
Figure 23 - Per-Channel Tristate Characteristics at all Data Rates
51
Zarlink Semiconductor Inc.
MT90840
Data Sheet
tclk
tclkh
tt
C4/8R1**
(8.192 MHz
reference)
STo0-7
tclkl
tsod
bit 7, ch. 0
bit 0, ch.127
tstis
bit 6, ch. 0
tstih
bit 7
STi0-7
tdf
tdf
F0o output
(8 kHz)
Frame Sync with Positive Polarity (SPFP = 1)
tclk
tt
tclkh
C4/8R1**
(8.192 MHz
reference)
STo0-7
tclkl
tsod
bit 7, ch. 0
bit 0, ch.127
tstis
STi0-7
bit 6, ch. 0
tstih
bit 7
tdf
tdf
F0o output
(8 kHz)
Frame Sync with Negative Polarity (SPFP = 0)
** In TM2 and TM3 operation at 8.192 Mbps, the F0 output signal is clocked by the C4/8R1 input reference provided by
the user. (In 8.192 Mbps applications, the SPCKo output signal is not used.)
Figure 24 - Serial Port Timing for 8.192 Mbps - Timing Modes 2 and 3
52
Zarlink Semiconductor Inc.
MT90840
Data Sheet
TCP controls the clock-edge
on which the output changes.
PCKT/PCKR
byte m-1
PDo0-7
byte m+1
byte m
tcdf
TCP = 1
CTo corresponding to
byte m
CTo0-3
CTo corresponding to
byte m+1
PCKT/PCKR
byte m-1
PDo0-7
byte m+1
byte m
tcdf
TCP = 0
CTo corresponding to
byte m
CTo0-3
CTo corresponding to
byte m+1
Figure 25 - Timing for the Parallel Port External Control Lines CTo0-3
tclk
tclkh
tclkl
PCKT
tza
PDo0-7
tristate
taz
tsod
byte n
byte 0
byte 1
tristate
n = 2429, 2047, or 809
PPFTi (PPFP=1)
tPPFS
tPPFH
Figure 26 - TM1 Parallel Port Transmit Timing (TM1 & PFDI = 1, PPFT is an input)
53
Zarlink Semiconductor Inc.
MT90840
Data Sheet
tclk
tclkh
tclkl
PCKT/PCKR
tza
PDo0-7
tristate
tsod
taz
byte 0
byte n
byte 1
tdf
tdf
PPFTo (PPFP=1)
tdf
tdf
PPFTo (PPFP=0)
Note: The depicted output timing occurs when TCP = 0. If TCP = 1, the byte at PDo0-7 port and the PPFT line will be
output on the falling edge of the PCKT/PCKR clock.
Figure 27 - Parallel Port Transmit Timing (PFDI = 0, PPFT is an output)
tclkh
tclkl
PCKR
tclk
tstis
PDi0-7
tstih
Byte 1
Byte 0
tfs
tfh
PPFRi
Figure 28 - Parallel Port Receive Timing
54
Zarlink Semiconductor Inc.
tristate
MT90840
Data Sheet
AC Electrical Characteristics - Parallel Data Port
Characteristics
Sym.
Min.
Typ.‡
Max.
Units
Test Conditions
1
PCKT/PCKR clock period
tclk
50
ns
2
PCKT/PCKR HIGH time
tclkh
20
ns
3
PCKT/PCKR LOW time
tclkl
20
ns
4
PPFTo output delay
from PCKR/PCKT transmit edge
tdf
28
30
ns
CL=30pF
CL=50pF
5
PDo output delay
from PCKR/PCKT transmit edge
tsod
28
30
ns
CL=30pF
CL=50pF
6
CTo0-3 output delay
from PCKR/PCKT transmit edge
tcdf
26
28
ns
CL=30pF
CL=50pF
7
PDo delay from Active to High-Z
tza
26
ns
CL=30pF, RL=1K
8
PDo delay from High-Z to Active
taz
28
ns
CL=30pF, RL=1K
9
PPFRi Setup Time
from PCKR sampling edge
tfrs
5
ns
10
PPFRi Hold Time
from PCKR sampling edge
tfrh
8
ns
11
PDi Set-up Time
from PCKR sampling edge
tstis
5
ns
12
PDi Hold Time
from PCKR sampling edge
tstih
8
ns
13
PPFTi Input Setup Time
from PCKT sampling edge
tppfs
5
ns
TM1, PFDI = 1
14
PPFTi Input Hold Time
from PCKT sampling edge
tppfh
5
ns
TM1, PFDI = 1
C4/8R1 or C4/8R2 at 4.096
tpv
-100
+100
ns
Jitter between PCKT/PCKR and
MHz with 50% duty cycle
C4 serial port clock.
Typical figures are at 25°C and are for design aid only: not guaranteed and not subject to production testing.
15
‡
PCKR
PPFRi
tdf
PPFT
TCP = 0
tdf
PPFT
TCP = 1
Note: For the PPFT depicted above, PPFP = HIGH. If PPFP is LOW, the PPFT line will have negative pulse polarity.
Figure 29 - Parallel Port in Timing Mode 4
55
Zarlink Semiconductor Inc.
MT90840
STo (4 Mbps)
Ch. 3 Bit 1
Data Sheet
Ch. 3 Bit 0 (4 Mbps)
Ch. 4 Bit 7
C4/8R1 or C4/8R2
(ST-BUS Mode)
tpv
tpv
PCKT
PPFTo
n-2
PDo7-0
n-1
n
0
1
2
Note: The MT90840 will correct phase relation in TM1 by moving PPFTo (by moving F0o in TM2 andTM3).
Figure 30 - Phase Variation Between C4/8R1 & C4/8R2 and PCKT Inputs for TM1 Operation
STo (4 Mbps)
Ch. 61 Bit 2
Ch. 61 Bit 1 (4 Mbps)
Ch. 61 Bit 0
SPCKo
(ST-BUS Mode)
tpv
tpv
0
1
PCKR
PPFRi
PDi7-0
n-1
n
2
Note: The MT90840 will correct phase relation in TM2 by inverting SPCKo w.r.t. C4/8R1 or C4/8R2.
Figure 31 - Phase Variation Between C4 and PCKR Inputs for TM2 Operation
56
Zarlink Semiconductor Inc.
MT90840
Data Sheet
AC Electrical Characteristics† - Intel/National- HPC Multiplexed Bus Mode - Voltages are with respect to ground
(VSS) unless otherwise stated.
Characteristics
Typ.‡
Sym.
Min.
Max.
1 ALE pulse width
talw
10
ns
2 Address setup from ALE falling
tads
5
ns
3 Address hold from ALE falling
tadh
5
ns
4 RD Active after ALE falling
talrd
15
ns
5 Data setup from DTA LOW on read
tddr
0
ns
6 CS hold after RD/WR
tcsrw
0
ns
7 CS setup from RD
tcsr
0
ns
8 Data hold after RD
tdhr
10
15
9 WR delay after ALE falling
talwr
15
ns
10 CS setup from WR
tcsw
0
ns
11 Data setup from WR
tdsw
10
ns
12 Data hold after WR Inactive
tdhw
0
ns
13 RD/WR Inactive to ALE Falling Edge
trst
23
ns
14 Acknowledgment hold time
takh
0
15 Data Delay on Reading Registers
22
30
Units
ns
ns
Test
Conditions/Notes
CL=150 pF on DTA,
and 30 pF on AD0-7.
CL=30 pF
CL=150 pF
20
ns
CL=150 pF, RL=1kΩ*
trdd
47
68
ns
ns
CL=30 pF
CL=150 pF
16 Acknowledgment Delay
Reading Registers
takd-rd
73
85
ns
ns
CL=30 pF
CL=150 pF
Acknowledgment Delay
Writing Registers
takd-wr
32
41
ns
ns
CL=30 pF
CL=150 pF
1 to 5 C4 cycles +
register takd-rd
.5 to 4 C4 cycles +
register takd-rd
1 to 3 PCKT/R cycles
+ register takd-rd
1 to 3 C4 cycles +
register takd-rd
Up to 3 PCKT/R cyc.
+ register takd-wr
Up to 3 C4 cycles +
register takd-wr
17 Acknowledgment Delay - Memories:
takd-mem
Reading TP Data Memory
244
488
1306
ns
Reading RP Data Memory
122
366
1062
ns
Reading TP Connection Memory
Reading RP Connection Memory
1 clock 2 clock 3 clk cyc +
takd-rd
cycle cycles
244
488
817
Writing TP Connection Memory**
takd-wr
Writing RP Connection Memory**
takd-wr
3 clk cyc +
takd-wr
774
ns
ns
† Timing is over recommended temperature & power supply voltages.
‡ Typical figures are at 25°C and are for design aid only: not guaranteed and not subject to production testing.
* High Impedance is measured by pulling to the appropriate rail with RL, with timing corrected to cancel time taken to discharge CL.
** Individual writes to Connection Memories will have Register Acknowledgment Delay. Burst writes to Connection Memories will have Read
Connection Memory Acknowledgment Delay.
57
Zarlink Semiconductor Inc.
MT90840
Data Sheet
talw
2.0V
ALE
0.8V
tads
AD0AD7
tadh
ADDRESS
2.0V
DATA
talrd
0.8V
tcsrw
2.0V
CS
0.8V
trst
2.0V
RD
tcsr
tdhr
0.8V
2.0V
WR
tdhw
tcsw
0.8V
tdsw
talwr
tddr
trdd
takh
2.0V
DTA
takd
Figure 32 - Intel/National Multiplexed Bus Timing
58
Zarlink Semiconductor Inc.
0.8V
MT90840
Data Sheet
AC Electrical Characteristics† - Motorola Multiplexed Bus Mode - Voltages are with respect to ground (VSS) unless
otherwise stated.
Characteristics
Sym.
Min.
Typ.‡
Max.
Units
1
AS pulse width
tasw
10
ns
2
Address setup from AS falling
tads
5
ns
3
Address hold from AS falling
tadh
5
ns
4
Data setup from DTA LOW on
read
tddr
0
ns
5
CS hold after DS falling
tcsh
0
ns
6
CS setup from DS rising
tcss
0
ns
7
Data setup on write
tdsw
10
8
Data hold after write
tdhw
0
ns
9
DS Inactive to AS Falling Edge
tdss
23
ns
10
R/W setup from DS rising
trws
5
ns
11
R/W hold after DS falling
trwh
5
ns
12
Data hold after read
tdhr
10
15
13
DS delay after AS falling
tdsh
15
14
Acknowledgment hold time
takh
0
15
Acknowledgment Delay:
Writing Registers
Acknowledgment Delay:
Reading Registers
22
30
ns
ns
Test
Conditions/Notes
CL=150 pF on DTA,
30 pF on AD0-7.
CL=30 pF
CL=150 pF
ns
20
ns
CL=150 pF,
RL=1kW*
takd-wr
32
41
ns
ns
CL=30 pF
CL=150 pF
takd-rd
73
85
ns
ns
CL=30 pF
CL=150 pF
59
Zarlink Semiconductor Inc.
MT90840
Data Sheet
AC Electrical Characteristics† - Motorola Multiplexed Bus Mode - Voltages are with respect to ground (VSS) unless
otherwise stated.
16
Min.
Typ.‡
Max.
Units
Reading TP Data Memory
244
488
1306
ns
Reading RP Data Memory
122
366
1062
ns
Reading TP Connection
Memory
1
clock
cycle
2 clock
cycles
Reading RP Connection
Memory
244
488
3 clk
cyc +
takd-rd
817
Writing TP Connection
Memory**
takd-wr
Writing RP Connection
Memory**
takd-wr
Characteristics
Sym.
Memory Acknowledgment Delay
takd-mem
3 clk
cyc +
takd-wr
774
ns
Test
Conditions/Notes
1 to 5 C4 cycles +
register takd-rd
.5 to 4 C4 cycles +
register takd-rd
1 to 3 PCKT/R
cycles + register
takd-rd
1 to 3 C4 cycles +
register takd-rd
Up to 3 PCKT/R
cyc. + register takd-wr
ns
Up to 3 C4 cycles +
register takd-wr
† Timing is over recommended temperature & power supply voltages.
‡ Typical figures are at 25°C and are for design aid only: not guaranteed and not subject to production testing.
* High Impedance is measured by pulling to the appropriate rail with RL, with timing corrected to cancel time taken to discharge CL.
** Individual writes to Connection Memories will have Register Acknowledgment Delay. Burst writes to Connection Memories will have Read
Connection Memory Acknowledgment Delay.
60
Zarlink Semiconductor Inc.
MT90840
Data Sheet
DS
2.0V
0.8V
trwh
trws
2.0V
R/W
0.8V
tdss
tasw
tdsh
2.0V
0.8V
AS
tads
AD0-7
WR
tdhw
tadh
2.0V
ADDRESS
DATA
0.8V
tdhr
AD0-13
RD
2.0V
ADDRESS
DATA
0.8V
tcss
2.0V
CS
0.8V
tddr
tcsh
takh
2.0V
DTA
0.8V
takd
Figure 33 - Motorola Multiplexed Bus Timing
61
Zarlink Semiconductor Inc.
MT90840
Data Sheet
tmssu
tmsh
TMS
tdih
ttclk
tdisu
TDI
ttclkh
ttclkl
TCK
tdod
TDO
ttrst
TRST
Figure 34 - Boundary Scan Test Port Timing
AC Electrical Characteristics - Boundary-Scan Test Port and RESET Pin
Parameter
Symbol
Min.
Max.
Units
1
TCK period width
t tclk
100
ns
2
TCK period width LOW
t tclkl
40
ns
3
TCK period width HIGH
t tclkh
40
ns
4
TDI setup time to TCK rising
tdisu
2
ns
5
TDI hold time after TCK rising
tdih
33
ns
6
TMS setup time to TCK rising
tmssu
2
ns
7
TMS hold time after TCK rising
t msh
5
ns
8
TDO delay from TCK falling
tdod
9
TRST pulse width
ttrst
15
ns
10
RESET pulse width
trst
15
ns
20
trst
RES
Figure 35 - RESET Timing
62
Zarlink Semiconductor Inc.
ns
Test Conditions
C L = 30 pF
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