High Temperature 83C51 Microcontroller
HT83C51
The HT83C51 is a monolithic 8-bit microcontroller that is pin
equivalent to the Intel 8XC51FC microcontroller. Fabricated with
Honeywell’s HTMOS™ dielectrically isolated high temperature
process, the HT83C51 is designed specifically for severe high
temperature applications such as downhole oil well, aerospace,
turbine engine and industrial control.
The HT83C51 uses the standard MCS-51 instruction set which is
optimized for control applications. Pin-for-pin equivalent to the MCS-51 series product, it is compatible with all known
development environments. Key features include the programmable counter array, watch dog timer, enhanced serial port
for multi-processor communication and a hierarchical interrupt structure. Software selectable idle is included for reduced
power. The HT83C51 varies from the standard 83C51FC, in that it supports half-duplex serial communication, and has 8k
Bytes of Mask programmable ROM. The device is available in a standard pinout DIP, with optional packages considered.
These microcontrollers provide guaranteed performance supporting operating frequencies in excess of 16 MHz over the
full -55 to +225ºC temperature range. Typically, parts will operate up to +300ºC for a year, with derated performance.
APPLICATIONS
Downhole Oil Well, Avionics, Turbine Engine Control, Industrial Process Control, Nuclear Reactor, Electric Power
Conversion, and Heavy Duty Internal Combustion Engine
FEATURES
Specified Over -55 to +225°C
On-Chip Oscillator
8-bit CPU Optimized for 5 Volt Control Applications
Structure with Seven Sources and Four Priority
Interrupt
Levels
Four 8-bit Bidirectional Parallel Ports
Duplex Programmable Serial Port with Framing Error
Half
Detection and Automatic Address Recognition
Three 16-bit Timer/Counters with One Up/Down
Timer/Counter and Clock Out
256 Bytes Internal Data Memory
64K External Data Memory Address Space
Hermetic 40-pin Ceramic Dip
MCS-51 Compatible Instructions Set
Parts burned in at 250ºC
Programmable Counter Array with:
Capture/Compare, Software Timer with Watchdog Capability, High Speed Output, and Pulse Width Modulator
HT83C51
FUNCTIONAL DIAGRAM
2
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HT83C51
PIN DESCRIPTIONS
VDD: +5V Supply Voltage
VSS: Circuit Ground
Port 0 (P0.0 – P0.7): Port 0 is an 8-bit bidirectional
I/O port. If external Program and/or Data memory
are used, port 0 cannot be used for general purpose
I/O. During accesses to external Program and Data
memory Port 0 is used as the low-order multiplexed
address and data bus. In this mode, Port 0 pins use
strong internal pullups when emitting 1’s, and are
TTL compatible. IF external Program and Data
memory are not used, Port 0 pins can be used as
general purpose I/O. When the Port pins have 1’s
written to them in I/O mode, the pins are floating
and can be driven as inputs. An external pullup is
required to generate logic high output in I/O mode.
Port 1 (P1.0-P1.7): Port 1 is an 8-bit bidirectional I/O
port with internal pullups. The output buffers can
drive TTL loads. When the Port 1 pins have 1’s
written to them, they are pulled high by the internal
pullups and can be used as inputs in this state. As
inputs, any pins that are externally pulled low will
source current because of the pullups. In addition,
Port 1 pins have the alternate uses shown in the
table below:
Port
Pin
Name
Alternate Function
P3.0
RXD
Serial port input
P3.1
TXD
Serial port output
P3.2
INT0n
External interrupt 0
P3.3
INT1n
External interrupt 1
P3.4
T0
External clock input for Timer 0
P3.5
T1
External clock input for Timer 1
P3.6
WRn
External Data Memory write strobe
P3.7
RDn
External Data Memory read strobe
Port 2 (P2.0-P2.7): Port 2 is an 8-bit bidirectional I/O
port with internal pullups. The output buffers can
drive TTL loads. When the Port 2 pins have 1’s
written to them, they are pulled high by the internal
pullups and can be used as inputs in this state. As
inputs, any pins that are externally pulled low will
source current because of the pullups.
Port 2 is used as the high-order address byte during
accesses to external Porgram Memory and during
accesses to external Data Memeory that use
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16-bit addressess (i.e. MOVX @DPTR). It uses
strong internal pullups when emitting 1’s in this
mode. During accesses to external Data Memory
that use 8 bit addresses, Port 2 emits the contents
of the P2 SFR.
Port 3 (P3.0-P3.7): Port 3 is an 8-bit bidirectional I/O
port with internal pullups. The output buffers can
drive TTL loads. When the Port 3 pins have 1’s
written to them, they are pulled high by the internal
pullpus and canb euses as iputs in this state. As
inputs, any pins that are externally pulled low will
source current because of the pullups. In addition,
Port 3 pins have the alternate uses shown in the
table below:
Port
Pin
Name
Alternate Function
P1.0
T2
External clock input to timer/clock out
P1.1
T2EX
Timer/Counter 2 Capture/Reload trigger and
direction control
P1.2
ECI
External count input to PCA
P1.3
CEX0
External I/O for PCA capture/compare Module 0
P1.4
CEX1
External I/O for PCA capture/compare Module 1
P1.5
CEX2
External I/O for PCA capture/compare Module 2
P1.6
CEX3
External I/O for PCA capture/compare Module 3
P1.7
CEX4
External I/O for PCA capture/compare Module 4
RST: Reset input. A high on this input for 2 or more
oscillator periods while the oscillatoris running
resets the device. All ports and Special Function
Registers will be reset to their default conditions.
Internal data memory is undefined after reset.
Program execution will begin within 12 oscillator
periods (one machine cycle) after the RST signal is
brought low. RST contains an internal pulldown
resistor to allow implementing power-up reset with
only an external capacitor.
ALE: Address Latch Enable. The ALE output is a
pulse for latching the low byte of the address during
th
accesses to output every 6 oscillator cycle and
may be used for external timing or clocking.
However, during each access to external Data
Memory (MOVX instruction), one ALE pulse is
skipped. If desired, ALE operation can be disabled
by setting bit 0 of SFR 8EH. When this bit is set,
ALE is active only during a MOVX instruction.
Otherwise, the pin is held low. When ALE is
disabled, program execution must be limited to the
internal 8K program ROM.
3
HT83C51
PSENn: Program Store Enable. This active low
signal is the read strobe to the external program
th
memory. PSENn is activated every 6 oscillator
cycle except that 2 PSENn activiations are skipped
during external data memory accesses.
EAn: External Access Enable. The EAn pin must
be strapped to VSS for the HT51 to fetch code from
external Program Memory locations 0000H to
1FFFH. The HT83C51 does not contain on-chip
program memory. If the EAn pin is held high then
code fetched from mrmory locations 0000H to
1FFFH will return all zeroes.
IDLE MODE
An instruction that sets the PCON. 0-bit causes that
to be the last instruction executed prior to going into
Idle mode. In the Idle mode, the internal clock to
the CPU is gated off but not to the Interrupt, Timer,
and Serial Port functions. The PCA can be
programmed to either pause or continue operating
during Idle Mode. The CPU status is completely
preserved and all registers maintain their previous
values during Idle Mode. The port pins hold the
logical vlaues that they had at the time the Idel
mode was activated. ALE and PSENn hold at logic
high levels.
XTAL 1: Input to the inverting oscillator amplifier.
XTAL2: Output from the inverting oscillator
amplifier.
OSCILLATOR CHARACTERISTICS
The input is XTAL1 and the output is XTAL2 for an
inverting amplifier which can be used as an on-chip
oscillator as shown in Figure 1. Make sure to
qualify the crystal or alternate timing source over
the temperature range of the intended application.
If an external clock source such as the HTOSC is
used , XTAL1 should be driven whil XTAL2 floats as
shown in Figure 2. There are no duty cycle
requirements on the external clock signal, but
minimum and maximum high and low times must be
observed
Idle mode can be terminated in two ways.
Activiation of any enabled interrupt will cause te
PCON. 0-bit to be cleared by hardware, terminating
Idle mode. The interrupt will be serviced, and
following the RETI instruction execution, the
instruction after the one that caused Idle mode will
be executed. Recovery from Idle mode is 3
oscillator periods plus 3 instruction cycles.
The other way that Idle mode can be terminated is
through a hardware reset, which ca be
accomplished by holding the RST pin high for 4
clock periods while the clock is running. Exiting Idle
mode with a hardware reset will retain the contents
of the on-chip RAM but the values in the SRFs will
be lost and program execution will begin at address
0.
MEMORY
The HT51 has a separate address space for
Program and Data Memory. Internally the HT51
contains 256 bytes of Data Memory. It can address
up to 64 Kbytes of external Data Memory and 64
Kbytes of external Program Memory. All program
memory is internal.
The EAn pin must be tied to Vss (ground) to enable
access to external program memory. When the
EAn pin is tied to Vdd, program fetches to
addresses 0000H and 1FFFH will return all zeroes.
The EAn pin must be tied to Vss (ground) to enable
access to external program memory locations
0000H through 1FFFH.
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HT83C51
The HT51 implements 256 bytes of internal data
RAM. The upper 128 bytes of this RAM occupy a
parallel address space to the Special Function
Registers (SFR’s). The CPU determines if the
internal access to an address above 7FH is to the
upper 128 bytes of RAM or to the SFR space by the
addressing mode of the instruction. If direct
addressing is used, the access is to the SFR space.
If indirect addressing is used, the acess is to the
internal RAM. Stack operations are indirectly
addressed so the upper portion of RAM can be
used as stack space.
INTERRUPTS
TIMER/COUNTERS
Serial port interrupt enable
The HT51 contains three 16-bit timer/counters.
Each of these are made up to two 8-bit registers
(THx, TLx where x=0, 1, or 2). Each of these three
can operate in either timer or counter mode. In the
timer mode, the TLx register is incremented once
every machine cycle (12 oscillator periods). The
th
count rate is 1/12 of the oscillator frequency. In
counter mode, the register is incremented when a 1
to 0 transition is detected on the alternate function
input corresponding to that timer (Tx where x=0, 1,
or 2). The maximum rate of count in counter mode
th
that the HT51 can detect is 1/24 of the oscillator
frequency.
Timer 1 interrupt enable
PCA COUNTER/TIMER
The Programmable Counter Array (PCA) contains a
single 16-bit counter/timer made up of the CL and
CH registers. This timer is used by all 5
capture/compare modules. Its clock input can be
programmed to be from one of four sources. These
are the oscillator frequency divided by 12, the
oscillator frequency divided by 4, Timer 0 overfllow,
and an external clock input, ECI, on the alternate
function of port pin P1.2.
SERIAL PORT
There are seven interrupt sources in the HT51.
Two are external interrupts (INT0n, INT1n), three
are timer interrupts (Timer 0, Timer 1, and Timer 2),
one is a PCA interrupt, and one is a serial port
interrupt as shown below.
PCA interrupt enable
Timer 2 interrupt enable
External interrupt 1 enable
Timer 0 interrupt enable
External interrupt 0 enable
RESET
The reset input is the RST pin. A reset is
accomplished by holding the RST pin high for a
minimum of 4 clock periods while the clock is
running. The CPU generates an internal reset from
the external signal. The port pins are driven to the
reset state 2 oscillator periods after a valid 1 is
detected on the RST pin.
While RST is high, PSENn is pulled high, ALE is
pulled low, and the port pins are pulled weakly high.
All SFRs are reset to their reset values. The
internal Data Memory content is not affected by
reset. In addition, if the HT51 is in Idle or Power
Down mode prior to activation of RST, the HT51 will
be taken out of Idle or Power Down mode by the
reset.
Mode
Description
Baud Rate
0
8-bit shift
register
1/12 times oscillator freq.
The processor will begin operation on the second
machine cycle after the RST line is brought low. A
memory access will be made immediately after the
RST line is brought low, but the data is not brought
into the processor. The memory access will be
repeated on the next machine cycle and actual
processing will begin at that time.
1
8-bit UART
Variable
INSTRUCTION SET
2
9-bit UART
1/64 or 1/32 times oscillator freq.
3
9-bit UART
variable
The serial port has physically separate receive and
transmit buffers, automoatic address recognition
and four modes of operation as shown below.
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The instruction set for the HT51 is compatible to the
Intel MCS-51 instruction set used on the 8XC51FC.
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HT83C51
AC CHARACTERISTICS
The AC characteristics for the HT51 are shown in
the following tables. Each of the timing symbols
has 5 characters. The first character is always a ‘T’
(Time). The other characters, depending on their
positions, stand for the logical name of a signal or
the logical status of that signal. The following is a
list of the characters and what they stand for:
A: Address
Q: Output Data
C: Clock
R: RDn Signal
D: Data
T: Time
H: Logic Level HIGH
V: Valid
I: Instruction (program memory
contents)
W: WRn Signal
L: Logic level LOW, or ALE
level
X: No longer a valid logic
P: PSENn
Z: Float
For example, TAVLL = Time from address valid to
ALE low. The characteristics given are over the
operating conditions TA=-55ºC to +225ºC,
VDD=5V±10%, VSS = 0V. The load capacitance on
Port 0, ALE and PSENn=100 pF. Load capacitance
for all other outpus =50 pF. Inputs during AC
testing are to be driven at VDD – 0.5V for logic 1 and
0.45 V for logic 0. Timing measurements are to be
made at VIH min for logic 1 and VIL max for logic 0.
For timing purposes, a port pin is no longer floating
when a 100 mV change from load voltage occurs,
and begins to float when a 100 mV change from the
loaded VOL/VOH level occurs. Timing diagrams are
shown to illustrate the signal relationships depicted
in the tables.
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HT83C51
DC CHARACTERISTICS
Symbol
Parameter
Min
Max
Unit
Test Conditions
VIL
Input Low Voltage
VSS-0.3
0.8
VIH
Input High Voltage (except XTAL1, RST)
2.0
VDD+0.5
V
VIH1
Input High Voltage (XTAL1, RST)
3.85
VDD+0.5
V
VOL
Output Low Voltage
0.3
V
IOL=100µA
0.45
V
IOL=1.6µA
1.0
V
IOL=3.5µA
0.3
V
IOL=200 µA
0.45
V
IOL=3.2µA
1.0
V
IOL=7.0µA
4.2
V
IOH=-10 µA
3.8
V
IOH=-30 µA
3.0
V
IOH=-60 µA
4.2
V
IOH=-200 µA
3.8
V
IOH=-3.2 µA
3.0
V
IOH=-7.0 µA
VOL1
VOH
VOH1
Output Low Voltage
PSENn)
(1,2)
(1,2)
(Ports 1,2, and 3)
(Ports 0, ALE,
Output High Voltage (Ports 1,2, and 3, ALE,
PSENn)
Output High Voltage (Ports 0)
(3)
IIL
Logical 0 Input Current (Ports 1,2, and 3)
-50
µA
VIN = 0.45 V
ILI
Input Leakage Current (Port 0)
±10
µA
0.45 V < Vin < VDD
ITL
Logical 1 to 0 Transition Current (Ports 1,2,
and 3)
-650
µA
VIN = 2V
RRST
RST Pulldown Resistor
225
KW
CIO
Pin Capacintance
10 typical
pF
@1 MHz, 25ºC
IDD
Power Supply Current:
Operating
70
mA
16 MHz
Idle
15
mA
16MHz
10
(1) Under steady state (non-transient conditions, IOL must be limited externally as follows:
Maximum IOL per port pin
10mA
Maximum IOL per 8-bit port
-port 0
26mA
-port 1,2,3
15mA
Maximum total IOL for all output pins
71mA
(2) If OIL exceeds the test conditions, VOL may exceed the related specifications.
(3) Pins are not guaranteed to sink current greater than the listed test conditions.
ABSOLUTE MAXIMUM RATINGS (1)
Input Voltage, VDD to VSS
-0.5 to 7.0 V
Voltage On Any Pin to VSS
-.05 V to VDD + 0.3V
Power Dissipation
750 mW
Storage Temperature
-65 to +325ºC
IOL per Output Pin
15 mA
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7
HT83C51
EXTERNAL PROGRAM AND DATA MEMORY CHARACTERISTICS
8
Symbol
Parameter
Min
TCLCL
Clock Period
62.5
1/TCLCL
Oscillator Frequency
TLHLL
ALE Pulse Width
TAVLL
Max
Unit
ns
16
MHz
2 TCLCL-40
ns
Address Valid to ALE Low
TCLCL-40
ns
TLLAX
Address hold after ALE Low
TCLCL-30
ns
TLLIV
ALE low to Valid Instruction In
TLLPL
ALE Low to PSENn Low
TPLPH
PSENn Pulse Width
TPLIV
PSENn low to Valid Instruction In
TPXIX
Input Instruction hold after PSENn
TPXIZ
Input Instruction Float After PSENn
TPVIV
4 TCLCL-100
ns
TCLCL-30
ns
3 TCLCL-45
ns
3 TCLCL-105
0
ns
ns
TCLCL-25
ns
Address to Valid Instruction In
5 TCLCL-105
ns
TPLAZ
PSENn Low to Address Float
10
ns
TRLRH
RDn Pulse Width
6 TCLCL-100
ns
TWLWH
WRn Pulse Width
6 TCLCL-100
ns
TRLDV
RDn Low to Valid Data In
TRHDX
Data Hold After RDn
TRHDZ
Data Float After RDn
2 TCLCL-60
ns
TLLDV
ALE Low to Valid Data In
8 TCLCL-150
ns
TAVDV
Address to Valid Data In
9 TCLCL-165
ns
TLLWL
ALE Low to RDn or WRn Low
3 TCLCL-50
3 TCLCL+50
ns
TAVWL
Address Valid to WRn Low
4 TCLCL-130
ns
TQVWX
Data Valid Before WRn
TCLCL-50
ns
TWHQX
Data Hold After WRn
TCLCL-50
ns
TQVWH
Data Valid to WRn High
7 TCLCL-150
ns
TRLAZ
RDn Low to Address Float
TWHLH
RDn or WRn High to ALE High
5 TCLCL-165
0
TCLCL-40
ns
ns
0
ns
TCLCL+40
ns
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HT83C51
EXTERNAL PROGRAM MEMORY READ CYCLE
EXTERNAL DATA MEMORY READ CYCLE
EXTERNAL DATA MEMORY WRITE CYCLE
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9
HT83C51
SERIAL PORT TIMING CHARACTERISTICS – SHIFT REGISTER MODE (MODE 0)
Symbol
TXLXL
TQVXH
TXHQX
TXHDX
TXHDV
Parameter
Serial Port Clock Period
Output Data Setup to Clock Rising Edge
Output Data Hold after Clock Rising Edge
Input Data Hold after Clock Rising Edge
Clock Rising Edge to Input Data Valid
16 MHz
Oscillator
Min
Max
750
492
8
0
492
Variable Oscillator
Min
12 TCLCL
10 TCLCL-133
2 TCLCL-117
0
Unit
Max
10 TCLCL-133
ns
ns
ns
ns
ns
SERIAL PORT TIMING WAVEFORMS
PERFORMANCE CURVES OVER TEMPERATURE
10
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HT83C51
DIFFERENCE BETWEEN INTEL
8XC51FC AND HT83C51
There are a few areas in which the HT51 differs
from the 8XC51FC. These differences will be
covered in this appendix. In this discussion,
8XC51FC will be used generically to refer to all
speed grades of the Intel 8XC51FC family,
including the 16MHz 8XC51FC-1.
1. Reset
The 8XC51FC requires the RST input to be held
high for at least 24 oscillator periods to guarantee
the reset is completed in the chip. Also, the port
pins are reset asynchronously as soon as the RST
pins is pulled high. On the HT51, all portions of
the chip are reset synchronously when the RST
pin has been high during 2 rising edges of the
input clock.
When coming out of reset, the 8XC51FC takes 1
to 2 machine cycles to begin driving ALE and
PSENn. The HT51 will begin driving ALE and
PSENn2 oscillator periods after the RST is
removed but the access during the first machine
cycle after reset is ignored by the processor. The
second cycle will repeat the access and
processing will begin.
5. DC Characteristics
VIL min for the 8XC51FC is -0.5V for all inputs
except EAn which has a VIL min of 0V. The HT51
has a VIL min for all inputs of Vss-0.3V.
6. Internal Program Memory
The 8XC51FC contains 32 Kbytes of internal
program ROM (8XC51FC) or EPROM (87C51FC).
The HT51 contains 8 Kbytes of internal program
ROM.
7. Serial Communications
There is a chance the part will miss hardware
interrupts when performing full-duplex
(simultaneous send and receive) communication or
when using the capture or compare modes in the
Programmable Counter Array (PCA).
As a result, the HT83C51 supports half-duplex
operation. Full duplex operation is not supported
without additional external hardware. Several
acceptable work-around procedures have been
identified for the problem associated with the PCA.
PINOUT DIAGRAM
2. Power Off Flag
The Power Off Flag in the PCON register has not
been implemented in the HT51.
3. On Circuit Emulation
The On Circuit Emulation mode of operation in the
8XC51FC has not been implemented in the HT51.
4. Operating Conditions
The operating voltage range for the 8XC51FC is
5V ± 20%. The operating temperature range is 0º
to 70ºC. On the HT51, the operating voltage
range is 5V ± 10%. The full speed operating
temperature rnage is -55ºC to +225ºC; typically,
parts will operate up to +300ºC for a year, with
derated performance.
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11
HT83C51
40-LEAD PACKAGE DETAIL
THERMAL CHARACTERISTICS
Assumes Static Air Convection
Θjc
0.9ºC/W
Θjc
32.8ºC/W
ORDERING INFORMATION
H
T
Process
T = Hi Temp SOI
Source
H = Honeywell
83C51
Part Type
83C51=
Microcontroller
C
D
Screening Level
C= Commercial
Package
D = Standard
DIP
Find out more
For more information on Honeywell’s High Temperature Electronics visit us online at www.hightempsolutions.com
or contact us at 1-800-323-8295. Customer Service Email: ps.customer.support@honeywell.com.
Honeywell reserves the right to make changes to improve reliability, function or design. Honeywell does not assume any liability arising out of
the application or use of any product or circuit described herein; neither does it convey any license under its patent rights nor the rights of
others.
Honeywell International Inc.
12001 Highway 55
Plymouth, MN 55441
Tel: 800-323-8295
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12
Form #900134
April 2011
©2011 Honeywell International Inc.
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