24AA128/24LC128/24FC128
128-Kbit I2C Serial EEPROM
Device Selection Table
VCC Range
Maximum Clock
Frequency
24AA128
1.7V-5.5V
400 kHz(1)
I
24LC128
2.5V-5.5V
400 kHz
I, E
MF, MS, P, SN, SM, MNY, ST
24FC128
1.7V-5.5V
1 MHz(2)
I
MF, MS, P, SN, SM, MNY, ST
Part Number
Note 1:
2:
Temperature
Ranges
Available Packages
MF, MS, P, SN, SM, MNY, ST
100 kHz for VCC < 2.5V.
400 kHz for VCC < 2.5V.
Features
Description
• Single Supply with Operation down to 1.7V for
24AA128/24FC128 devices, 2.5V for 24LC128
Devices
• Low-Power CMOS Technology:
- Write current 3 mA, maximum
- Standby current 1 µA, maximum (I-temp.)
• Two-Wire Serial Interface, I2C Compatible
• Cascadable up to Eight Devices
• Schmitt Trigger Inputs for Noise Suppression
• Output Slope Control to Eliminate Ground Bounce
• 100 kHz, 400 kHz and 1 MHz Compatibility
• Page Write Time: 5 ms, Maximum
• Self-Timed Erase/Write Cycle
• 64-Byte Page Write Buffer
• Hardware Write-Protect
• ESD Protection > 4,000V
• More than 1 Million Erase/Write Cycles
• Data Retention > 200 years
• Factory Programming Available
• RoHS Compliant
• Temperature Ranges:
- Industrial (I):
-40C to +85C
- Extended (E)
-40C to +125C
The Microchip Technology Inc. 24XX128(1) is a 16K x 8
(128 Kbit) Serial Electrically Erasable PROM
(EEPROM), capable of operation across a broad
voltage range (1.7V to 5.5V). It has been developed for
advanced, low-power applications such as personal
communications or data acquisition. This device also
has a page write capability of up to 64 bytes of data.
This device is capable of both random and sequential
reads up to the 128K boundary. Functional address
lines allow up to eight devices on the same bus, for up
to 1 Mbit address space.
Note 1: 24XX128 is used in this document as a
generic
part
number
for
the
24AA128/24LC128/24FC128 devices.
Package Types
PDIP/MSOP (1)
1
A1
2
A2
3
VSS
4
8 VCC
A0
1
7 WP
A1
2
A2
3
VSS
4
6 SCL
5 SDA
8
VCC
7
WP
6
SCL
5
SDA
Packages
• 8-Lead DFN, 8-Lead MSOP, 8-Lead PDIP,
8-Lead SOIC, 8-Lead SOIJ, 8-Lead TDFN and
8-Lead TSSOP
Note
1:
A0
1
A1
2
A2
3
VSS
4
24XX128
SOIC/SOIJ/TSSOP
• Automotive AEC-Q100 Qualified
2010-2021 Microchip Technology Inc. and its subsidiaries
24XX128
A0
24XX128
DFN/TDFN
8
VCC
7
WP
6
SCL
5
SDA
Pins A0 and A1 are no-connects for the MSOP
package only.
DS20001191U-page 1
24AA128/24LC128/24FC128
Block Diagram
A0 A1 A2 WP
I/O
Control
Logic
Memory
Control
Logic
HV Generator
XDEC
EEPROM
Array
Page Latches
I/O
SCL
YDEC
SDA
VCC
VSS
DS20001191U-page 2
Sense Amp.
R/W Control
2010-2021 Microchip Technology Inc. and its subsidiaries
24AA128/24LC128/24FC128
1.0
ELECTRICAL CHARACTERISTICS
Absolute Maximum Ratings(†)
VCC.............................................................................................................................................................................6.5V
All inputs and outputs w.r.t. VSS ..........................................................................................................-0.6V to VCC +1.0V
Storage temperature ............................................................................................................................... -65°C to +150°C
Ambient temperature with power applied................................................................................................ -40°C to +125°C
ESD protection on all pins 4 kV
† NOTICE: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the
device. This is a stress rating only and functional operation of the device at those or any other conditions above those
indicated in the operational listings of this specification is not implied. Exposure to maximum rating conditions for
extended periods may affect device reliability.
TABLE 1-1:
DC CHARACTERISTICS
Industrial (I):
Extended (E):
DC CHARACTERISTICS
Param.
Symbol
No.
D1
VIH
Characteristic
High-Level Input Voltage
Minimum
VCC = +1.7V to 5.5V TA = -40°C to +85°C
VCC = +2.5V to 5.5V TA = -40°C to +125°C
Maximum
Units
Conditions
0.7 VCC
—
V
—
0.3 VCC
V
VCC 2.5V
—
0.2 VCC
V
VCC < 2.5V
0.05 VCC
—
V
VCC 2.5V (Note 1)
D2
VIL
Low-Level Input Voltage
D3
VHYS
Hysteresis of Schmitt Trigger
Inputs (SDA, SCL pins)
D4
VOL
Low-Level Output Voltage
—
0.40
V
IOL = 3.0 mA @ VCC = 4.5V
IOL = 2.1 mA @ VCC = 2.5V
D5
ILI
Input Leakage Current
—
±1
µA
VIN = VSS or VCC, WP = VSS
VIN = VSS or VCC, WP = VCC
D6
ILO
Output Leakage Current
—
±1
µA
VOUT = VSS or VCC
D7
CIN,
COUT
Pin Capacitance
(all inputs/outputs)
—
10
pF
VCC = 5.0V (Note 1)
TA = +25°C, FCLK = 1 MHz
D8
ICC Read
—
400
µA
VCC = 5.5V, SCL = 400 kHz
D9
ICC Write
—
3
mA
VCC = 5.5V
—
1
µA
SDA = SCL = VCC = 5.5V
A0, A1, A2, WP = VSS, I-Temp
—
5
µA
SDA = SCL = VCC = 5.5V
A0, A1, A2, WP = VSS, E-Temp
D10
Note 1:
ICCS
Operating Current
Standby Current
This parameter is periodically sampled and not 100% tested.
2010-2021 Microchip Technology Inc. and its subsidiaries
DS20001191U-page 3
24AA128/24LC128/24FC128
TABLE 1-2:
AC CHARACTERISTICS
Industrial (I):
Extended (E):
AC CHARACTERISTICS
Param.
Symbol
No.
1
FCLK
2
THIGH
3
TLOW
4
TR
5
TF
Characteristic
Clock Frequency
Clock High Time
Clock Low Time
SDA and SCL Rise Time
SDA and SCL Fall Time
THD:STA Start Condition Hold Time
6
7
TSU:STA Start Condition Setup Time
8
THD:DAT Data Input Hold Time
9
TSU:DAT Data Input Setup Time
TSU:STO Stop Condition Setup Time
10
Note 1:
2:
3:
4:
VCC = +1.7V to 5.5V TA = -40°C to +85°C
VCC = +2.5V to 5.5V TA = -40°C to +125°C
Minimum Maximum Units
Conditions
—
100
kHz
1.7V VCC 2.5V
—
400
kHz
2.5V VCC 5.5V
—
400
kHz
1.7V VCC 2.5V (24FC128)
—
1000
kHz
2.5V VCC 5.5V (24FC128)
4000
—
ns
1.7V VCC 2.5V
600
—
ns
2.5V VCC 5.5V
600
—
ns
1.7V VCC 2.5V (24FC128)
500
—
ns
2.5V VCC 5.5V (24FC128)
4700
—
ns
1.7V VCC 2.5V
1300
—
ns
2.5V VCC 5.5V
1300
—
ns
1.7V VCC 2.5V (24FC128)
500
—
ns
2.5V VCC 5.5V (24FC128)
—
1000
ns
1.7V VCC 2.5V (Note 1)
—
300
ns
2.5V VCC 5.5V (Note 1)
—
300
ns
1.7V VCC 5.5V (24FC128)
(Note 1)
—
300
ns
All except, 24FC128 (Note 1)
—
100
ns
1.7V VCC 5.5V (24FC128)
(Note 1)
4000
—
ns
1.7V VCC 2.5V
600
—
ns
2.5V VCC 5.5V
600
—
ns
1.7V VCC 2.5V (24FC128)
250
—
ns
2.5V VCC 5.5V (24FC128)
4700
—
ns
1.7V VCC 2.5V
600
—
ns
2.5V VCC 5.5V
600
—
ns
1.7V VCC 2.5V (24FC128)
250
—
ns
2.5V VCC 5.5V (24FC128)
0
—
ns
Note 2
250
—
ns
1.7V VCC 2.5V
100
—
ns
2.5V VCC 5.5V
100
—
ns
1.7V VCC 5.5V (24FC128)
4000
—
ns
1.7V VCC 2.5V
600
—
ns
2.5V VCC 5.5V
600
—
ns
1.7V VCC 2.5V (24FC128)
250
—
ns
2.5V VCC 5.5V (24FC128)
Not 100% tested. CB = total capacitance of one bus line in pF.
As a transmitter, the device must provide an internal minimum delay time to bridge the undefined region
(minimum 300 ns) of the falling edge of SCL to avoid unintended generation of Start or Stop conditions.
The combined TSP and VHYS specifications are due to new Schmitt Trigger inputs, which provide improved
noise spike suppression. This eliminates the need for a TI specification for standard operation.
This parameter is not tested but ensured by characterization.
DS20001191U-page 4
2010-2021 Microchip Technology Inc. and its subsidiaries
24AA128/24LC128/24FC128
TABLE 1-2:
AC CHARACTERISTICS (CONTINUED)
Industrial (I):
Extended (E):
AC CHARACTERISTICS
Param.
Symbol
No.
11
TSU:WP
THD:WP
12
13
TAA
14
TBUF
Characteristic
WP Setup Time
WP Hold Time
Output Valid From Clock
Bus Free Time: The Time The
Bus Must Be Free Before a
New Transmission Can Start
VCC = +1.7V to 5.5V TA = -40°C to +85°C
VCC = +2.5V to 5.5V TA = -40°C to +125°C
Minimum Maximum Units
Conditions
4000
—
ns
1.7V VCC 2.5V
600
—
ns
2.5V VCC 5.5V
600
—
ns
1.7V VCC 5.5V (24FC128)
4700
—
ns
1.7V VCC 2.5V
1300
—
ns
2.5V VCC 5.5V
1300
—
ns
1.7V VCC 5.5V (24FC128)
—
3500
ns
1.7V VCC 2.5V (Note 2)
—
900
ns
2.5V VCC 5.5V (Note 2)
—
900
ns
1.7V VCC 2.5V (24FC128)
(Note 2)
—
400
ns
2.5V VCC 5.5V (24FC128)
(Note 2)
4700
—
ns
1.7V VCC 2.5V
1300
—
ns
2.5V VCC 5.5V
1300
—
ns
1.7V VCC 2.5V (24FC128)
500
—
ns
2.5V VCC 5.5V (24FC128)
10 +
0.1CB
250
ns
All except, 24FC128 (Note 1)
TOF
Output Fall Time from VIH
Minimum to VIL Maximum
CB 100 pF
—
250
ns
24FC128 (Note 1)
16
TSP
Input Filter Spike Suppression
(SDA and SCL pins)
—
50
ns
All except, 24FC128
(Notes 1 and Note 3)
17
TWC
Write Cycle Time
(byte or page)
—
5
ms
1,000,000
—
15
18
Endurance
Note 1:
2:
3:
4:
cycles +25°C, 5.5V, Page Mode (Note 4)
Not 100% tested. CB = total capacitance of one bus line in pF.
As a transmitter, the device must provide an internal minimum delay time to bridge the undefined region
(minimum 300 ns) of the falling edge of SCL to avoid unintended generation of Start or Stop conditions.
The combined TSP and VHYS specifications are due to new Schmitt Trigger inputs, which provide improved
noise spike suppression. This eliminates the need for a TI specification for standard operation.
This parameter is not tested but ensured by characterization.
2010-2021 Microchip Technology Inc. and its subsidiaries
DS20001191U-page 5
24AA128/24LC128/24FC128
FIGURE 1-1:
BUS TIMING DATA
5
SCL
7
SDA
IN
3
4
D3
2
8
10
9
6
16
14
13
SDA
OUT
WP
DS20001191U-page 6
(protected)
(unprotected)
11
12
2010-2021 Microchip Technology Inc. and its subsidiaries
24AA128/24LC128/24FC128
2.0
PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 2-1.
TABLE 2-1:
Name
PIN FUNCTION TABLE
DFN
(1)
MSOP
PDIP
SOIC
SOIJ
TDFN(1)
TSSOP
Function
A0
1
—
1
1
1
1
1
User Configurable Chip Select
A1
2
—
2
2
2
2
2
User Configurable Chip Select
A2
3
3
3
3
3
3
3
User Configurable Chip Select
VSS
4
4
4
4
4
4
4
Ground
SDA
5
5
5
5
5
5
5
Serial Address/Data I/O
SCL
6
6
6
6
6
6
6
Serial Clock
WP
7
7
7
7
7
7
7
Write-Protect Input
VCC
8
8
8
8
8
8
8
Power Supply
Note 1:
2.1
The exposed pad on the DFN/TDFN package can be connected to VSS or left floating.
A0, A1, A2 Chip Address Inputs
The A0, A1 and A2 inputs are used by the 24XX128 for
multiple device operations. The levels on these inputs
are compared with the corresponding bits in the client
address. The chip is selected if the compare is true.
Note:
For the MSOP package only, pins A0 and
A1 are not connected.
Up to eight devices (two for the MSOP package) may
be connected to the same bus by using different Chip
Select bit combinations. These inputs must be
connected to either VCC or VSS.
2.3
Serial Clock (SCL)
This input is used to synchronize the data transfer to
and from the device.
2.4
Write-Protect (WP)
This pin must be connected to either VSS or VCC. If tied
to VSS, write operations are enabled. If tied to VCC,
write operations are inhibited but read operations are
not affected.
In most applications, the chip address inputs A0, A1
and A2 are hardwired to logic ‘0’ or logic ‘1’. For
applications in which these pins are controlled by a
microcontroller or other programmable device, the chip
address pins must be driven to logic ‘0’ or logic ‘1’
before normal device operation can proceed.
2.2
Serial Data (SDA)
This is a bidirectional pin used to transfer addresses
and data into and out of the device. It is an open-drain
terminal. Therefore, the SDA bus requires a pull-up
resistor to VCC (typical 10 k for 100 kHz, 2 k for
400 kHz and 1 MHz).
For normal data transfer, SDA is allowed to change
only during SCL low. Changes during SCL high are
reserved for indicating the Start and Stop conditions.
2010-2021 Microchip Technology Inc. and its subsidiaries
DS20001191U-page 7
24AA128/24LC128/24FC128
3.0
FUNCTIONAL DESCRIPTION
The 24XX128 supports a bidirectional two-wire bus and
data transmission protocol. A device that sends data
onto the bus is defined as a transmitter and a device
receiving data as a receiver. The bus must be
controlled by a host device which generates the Serial
Clock (SCL), controls the bus access and generates
the Start and Stop conditions while the 24XX128 works
as a client. Both host and client can operate as a
transmitter or receiver, but the host device determines
which mode is activated.
4.0
BUS CHARACTERISTICS
The following bus protocol has been defined:
• Data transfer may be initiated only when the bus
is not busy.
• During data transfer, the data line must remain
stable whenever the clock line is high. Changes in
the data line while the clock line is high will be
interpreted as a Start or Stop condition.
Accordingly, the following bus conditions have been
defined (Figure 4-1).
4.1
4.4
Data Valid (D)
The state of the data line represents valid data when,
after a Start condition, the data line is stable for the
duration of the high period of the clock signal.
The data on the line must be changed during the low
period of the clock signal. There is one bit of data per
clock pulse.
Each data transfer is initiated with a Start condition and
terminated with a Stop condition. The number of the
data bytes transferred between the Start and Stop
conditions is determined by the host device and is,
theoretically, unlimited (although only the last 64 will be
stored when doing a write operation). When an
overwrite does occur, it will replace data in a
First-In First-Out (FIFO) principle.
4.5
Acknowledge
Each receiving device, when addressed, is obliged to
generate an Acknowledge signal after the reception of
each byte. The host device must generate an extra
clock pulse, which is associated with this Acknowledge
bit.
Note:
Bus Not Busy (A)
The 24XX128 does not generate any
Acknowledge bits if an internal
programming cycle is in progress.
Both data and clock lines remain high.
4.2
Start Data Transfer (B)
A high-to-low transition of the SDA line while the clock
(SCL) is high determines a Start condition. All
commands must be preceded by a Start condition.
4.3
Stop Data Transfer (C)
A low-to-high transition of the SDA line while the clock
(SCL) is high determines a Stop condition. All
operations must end with a Stop condition.
FIGURE 4-1:
(A)
A device that acknowledges must pull down the SDA
line during the Acknowledge clock pulse in such a way
that the SDA line is stable-low during the high period of
the Acknowledge-related clock pulse. Moreover, setup
and hold times must be taken into account. During
reads, a host must signal an end of data to the client by
not generating an Acknowledge bit on the last byte that
has been clocked out of the client. In this case, the
client (24XX128) will leave the data line high to enable
the host to generate the Stop condition.
DATA TRANSFER SEQUENCE ON THE SERIAL BUS
(B)
(D)
Start
Condition
Address or
Acknowledge
Valid
(D)
(C)
(A)
SCL
SDA
DS20001191U-page 8
Data
Allowed
to Change
Stop
Condition
2010-2021 Microchip Technology Inc. and its subsidiaries
24AA128/24LC128/24FC128
FIGURE 4-2:
ACKNOWLEDGE TIMING
Acknowledge
Bit
SCL
SDA
1
2
3
4
5
6
7
Data from transmitter
Transmitter must release the SDA line at this point,
allowing the Receiver to pull the SDA line low to
acknowledge the previous eight bits of data.
2010-2021 Microchip Technology Inc. and its subsidiaries
8
9
1
2
3
Data from transmitter
Receiver must release the SDA line
at this point, allowing the Transmitter
to continue sending data.
DS20001191U-page 9
24AA128/24LC128/24FC128
5.0
DEVICE ADDRESSING
FIGURE 5-1:
A control byte is the first byte received following the
Start condition from the host device. The control byte
consists of a 4-bit control code. For the 24XX128, this
is set as ‘1010’ binary for read and write operations.
The next three bits of the control byte are the Chip
Select bits (A2, A1, A0). The Chip Select bits allow the
use of up to eight 24XX128 devices on the same bus
and are used to select which device is accessed. The
Chip Select bits in the control byte must correspond to
the logic levels on the corresponding A2, A1 and A0
pins for the device to respond. These bits, in effect, are
the three Most Significant bits of the word address. The
combination of the 4-bit control code and the next three
bits are called the client address.
For the MSOP package, the A0 and A1 pins are not
connected. During device addressing, the A0 and A1
Chip Select bits (Figure 5-1 and Figure 5-2) should be
set to ‘0’. Only two 24XX128 MSOP packages can be
connected to the same bus.
The last bit of the control byte is the Read/Write (R/W)
bit and it defines the operation to be performed. When
set to a ‘1’, a read operation is selected. When set to
a ‘0’, a write operation is selected. The next two bytes
received define the address of the first data byte
(Figure 5-2). Because only A13…A0 are used, the
upper two address bits are “don’t care” bits. The upper
address bits are transferred first, followed by the Less
Significant bits.
Following the Start condition, the 24XX128 monitors
the SDA bus checking the device type identifier being
transmitted. Upon receiving a ‘1010’ code and
appropriate device select bits, the client device outputs
an Acknowledge signal on the SDA line. Depending on
the state of the R/W bit, the 24XX128 will select a read
or write operation.
FIGURE 5-2:
0
1
Read/Write Bit
Chip Select
Bits
Control Code
S
1
0
1
0
A2
A1
A0 R/W ACK
Client Address
Start Bit
5.1
Acknowledge Bit
Contiguous Addressing Across
Multiple Devices
The Chip Select bits A2, A1 and A0 can be used to
expand the contiguous address space for up to 1 Mbit
by adding up to eight 24XX128 devices on the same
bus. In this case, software can use A0 of the control
byte as address bit A14; A1 as address bit A15; and A2
as address bit A16. It is not possible to sequentially
read across device boundaries.
For the MSOP package, up to two 24XX128 devices
can be added for up to 256 Kbit of address space. In
this case, software can use A2 of the control byte as
address bit A16. Bits A0 (A14) and A1 (A15) of the
control byte must always be set to logic ‘0’ for the
MSOP.
ADDRESS SEQUENCE BIT ASSIGNMENTS
Control Byte
1
CONTROL BYTE
FORMAT
0
A
2
Control
Code
DS20001191U-page 10
A
1
Chip
Select
Bits
Address High Byte
A
0 R/W
x
x
A A A A
13 12 11 10
Address Low Byte
A
9
A
8
A
7
•
•
•
•
•
•
A
0
x = “don’t care” bit
2010-2021 Microchip Technology Inc. and its subsidiaries
24AA128/24LC128/24FC128
6.0
WRITE OPERATIONS
6.1
Byte Write
once the host has transmitted a Stop condition. Upon
receipt of each word, the six lower Address Pointer bits,
which form the byte counter, are internally incremented
by one. If the host should transmit more than 64 bytes
prior to generating the Stop condition, the address
counter will roll over and the previously received data
will be overwritten. As with the byte write operation,
once the Stop condition is received, an internal write
cycle will begin (Figure 6-1). If an attempt is made to
write to the array with the WP pin held high, the device
will acknowledge the command, but no write cycle will
occur, no data will be written and the device will immediately accept a new command.
Following the Start condition from the host, the control
code (4 bits), the Chip Select (3 bits) and the R/W bit
(which is a logic low) are clocked onto the bus by the
host transmitter. This indicates to the addressed client
receiver that the address high byte will follow after it
has generated an Acknowledge bit during the ninth
clock cycle. Therefore, the next byte transmitted by the
host is the high-order byte of the word address and will
be written into the Address Pointer of the 24XX128.
The next byte is the Least Significant Address Byte.
After receiving another Acknowledge signal from the
24XX128, the host device will transmit the data word to
be written into the addressed memory location. The
24XX128 acknowledges again and the host generates
a Stop condition. This initiates the internal write cycle
and during this time, the 24XX128 will not generate
Acknowledge signals (Figure 6-1). If an attempt is
made to write to the array with the WP pin held high, the
device will acknowledge the command, but no write
cycle will occur, no data will be written and the device
will immediately accept a new command. After a byte
write command, the internal address counter will point
to the address location following the one that was just
written.
Note:
6.2
Note:
Page write operations are limited to
writing bytes within a single physical
page, regardless of the number of
bytes actually being written. Physical
page boundaries start at addresses
that are integer multiples of the page
buffer size (or ‘page size’) and end at
addresses that are integer multiples of
page size – 1. If a page write
command attempts to write across a
physical page boundary, the result is
that the data wrap around to the beginning of the current page (overwriting
data previously stored there), instead
of being written to the next page, as
might be expected. It is, therefore,
necessary for the application software
to prevent page write operations that
would attempt to cross a page
boundary.
When doing a write of less than 64 bytes,
the data in the rest of the page are
refreshed along with the data bytes being
written. This will force the entire page to
endure a write cycle, for this reason
endurance is specified per page.
6.3
Page Write
The WP pin allows the user to write-protect the entire
array (0000-3FFF) when the pin is tied to VCC. If tied to
VSS the write protection is disabled. The WP pin is
sampled at the Stop bit for every write command
(Figure 1-1). Toggling the WP pin after the Stop bit will
have no effect on the execution of the write cycle.
The write control byte, word address and the first data
byte are transmitted to the 24XX128 in much the same
way as in a byte write. The exception is that instead of
generating a Stop condition, the host transmits up to 63
additional bytes, which are temporarily stored in the
on-chip page buffer and will be written into memory
FIGURE 6-1:
Bus Activity
Host
SDA Line
Bus Activity
Write Protection
BYTE WRITE
S
T
A
R
T
Control
Byte
Address
High Byte
AA
S1010A
2 10 0
Address
Low Byte
S
T
O
P
Data
xx
A
C
K
2010-2021 Microchip Technology Inc. and its subsidiaries
P
A
C
K
A
C
K
A
C
K
x = “don’t care” bit
DS20001191U-page 11
24AA128/24LC128/24FC128
FIGURE 6-1:
PAGE WRITE
Bus Activity
Host
S
T
A
R
T
SDA Line
AAA
S10102 1 00
Bus Activity
Control
Byte
Address
High Byte
Address
Low Byte
S
T
O
P
Data Byte 63
Data Byte 0
P
xx
A
C
K
A
C
K
A
C
K
A
C
K
A
C
K
x = “don’t care” bit
7.0
ACKNOWLEDGE POLLING
Since the device will not acknowledge during a write
cycle, this can be used to determine when the cycle is
complete (this feature can be used to maximize bus
throughput). Once the Stop condition for a write command has been issued from the host, the device initiates the internally timed write cycle. ACK polling can be
initiated immediately. This involves the host sending a
Start condition, followed by the control byte for a write
command (R/W = 0). If the device is still busy with the
write cycle, then no ACK will be returned. If no ACK is
returned, the Start bit and control byte must be resent.
If the cycle is complete, then the device will return the
ACK and the host can then proceed with the next read
or write command. See Figure 7-1 for flow diagram.
FIGURE 7-1:
ACKNOWLEDGE
POLLING FLOW
Send
Write Command
Send Stop
Condition to
Initiate Write Cycle
Send Start
Send Control Byte
with R/W = 0
Did Device
Acknowledge
(ACK = 0)?
No
Yes
Next
Operation
DS20001191U-page 12
2010-2021 Microchip Technology Inc. and its subsidiaries
24AA128/24LC128/24FC128
8.0
READ OPERATION
8.2
Random read operations allow the host to access any
memory location in a random manner. To perform this
type of read operation, the word address must first be
set. This is done by sending the word address to the
24XX128 as part of a write operation (R/W bit set to
‘0’). Once the word address is sent, the host generates
a Start condition following the Acknowledge. This
terminates the write operation, but not before the
internal Address Pointer is set. The host then issues
the control byte again, but with the R/W bit set to a ‘1’.
Read operations are initiated in much the same way as
write operations with the exception that the R/W bit of
the control byte is set to one. There are three basic
types of read operations: current address read, random
read and sequential read.
8.1
Current Address Read
The 24XX128 contains an address counter that
maintains the address of the last word accessed,
internally incremented by one. Therefore, if the
previous read access was to address n (n is any legal
address), the next current address read operation
would access data from address n + 1.
The 24XX128 will then issue an Acknowledge and
transmit the 8-bit data word. The host will not
acknowledge the transfer but does generate a Stop
condition, which causes the 24XX128 to discontinue
transmission (Figure 8-2). After a random read
command, the internal address counter will point to the
address location following the one that was just read.
Upon receipt of the control byte with R/W bit set to ‘1’,
the 24XX128 issues an Acknowledge and transmits the
8-bit data word. The host will not acknowledge the
transfer, but does generate a Stop condition and the
24XX128 discontinues transmission (Figure 8-1).
FIGURE 8-1:
S
T
A
R
T
SDA Line
S 1 0 1 0 A AA 1
2 1 0
P
A
C
K
FIGURE 8-2:
Sequential Read
Sequential reads are initiated in the same way as a
random read except that after the 24XX128 transmits
the first data byte, the host issues an Acknowledge (as
opposed to the Stop condition used in a random read).
This Acknowledge directs the 24XX128 to transmit the
next sequentially addressed 8-bit word (Figure 8-3).
Following the final byte transmitted to the host, the host
will not generate an Acknowledge but will generate a
Stop condition.
S
T
O
P
Data
Byte
Control
Byte
Bus Activity
N
O
To provide sequential reads, the 24XX128 contains an
internal Address Pointer which is incremented by one
at the completion of each operation. This Address
Pointer allows the entire memory contents to be serially
read during one operation. The internal Address
Pointer will automatically roll over from address 3FFF
to address 0000 if the host acknowledges the byte
received from the array address 3FFF.
A
C
K
RANDOM READ
S
T
A
R
T
Bus Activity
Host
SDA Line
8.3
CURRENT ADDRESS
READ
Bus Activity
Host
Random Read
Control
Byte
Address
High Byte
S1010AAA0
2 1 0
Bus Activity
S
T
A
R
T
Address
Low Byte
xx
A
C
K
x = “don’t care” bit
2010-2021 Microchip Technology Inc. and its subsidiaries
A
C
K
A
C
K
Control
Byte
S 1 0 1 0 A A A1
2 1 0
S
T
O
P
Data
Byte
P
A
C
K
N
O
A
C
K
DS20001191U-page 13
24AA128/24LC128/24FC128
FIGURE 8-3:
Bus Activity
Host
SEQUENTIAL READ
Control
Byte
Data (n)
Data (n + 1)
Data (n + 2)
P
SDA Line
Bus Activity
DS20001191U-page 14
S
T
O
P
Data (n + x)
A
C
K
A
C
K
A
C
K
A
C
K
N
O
A
C
K
2010-2021 Microchip Technology Inc. and its subsidiaries
24AA128/24LC128/24FC128
9.0
PACKAGING INFORMATION
9.1
Package Marking Information
8-Lead DFN-S
Example
XXXXXXX
XXXXXXX
YYWW
NNN
24LC128
I/MF
2136
13F
8-Lead MSOP
Example
XXXXXX
4L128I
YWWNNN
13613F
8-Lead PDIP (300 mil)
Example
XXXXXXXX
XXXXXNNN
YYWW
24AA128
I/P e3 13F
2136
8-Lead SOIC (3.90 mm)
XXXXXXXX
XXXXYYWW
NNN
2010-2021 Microchip Technology Inc. and its subsidiaries
Example
24LC128I
SN e3 2136
13F
DS20001191U-page 15
24AA128/24LC128/24FC128
Package Marking Information (Continued)
8-Lead SOIJ (5.28 mm)
Example
XXXXXXXX
XXXXXXXX
YYWWNNN
24LC128
I/SM e3
213613F
8-Lead 2x3 TDFN
Example
XXX
YWW
NN
A84
136
13
Example
8-Lead TSSOP
XXXX
XYWW
NNN
4LC
I136
13F
1st Line Marking Codes
Part Number
TSSOP
MSOP
SOIC
SOIJ
PDIP
DFN
(1)
24AA128T(1)
TDFN
I-Temp
E-Temp
24AA128
4AC
4A128T
24AA128
24AA128
24AA128
A81
—
24LC128
4LC
4L128T(1)
24LC128T(1)
24LC128
24LC128
24LC128
A84
A85
24FC128
4FC
4F128T(1)
24FC128T(1)
24FC128
24FC128
24FC128
A8A
—
Note 1:
T = Temperature grade (I, E)
Legend: XX...X
T
Y
YY
WW
NNN
e3
*
Part number or part number code
Temperature (I, E)
Year code (last digit of calendar year)
Year code (last 2 digits of calendar year)
Week code (week of January 1 is week ‘01’)
Alphanumeric traceability code (2 characters for small packages)
JEDEC® designator for Matte Tin (Sn)
Standard OTP marking consists of Microchip part number, year code, week
code and traceability code.
Note:
For very small packages with no room for the JEDEC® designator
e3 , the marking will only appear on the outer carton or reel label.
Note:
In the event the full Microchip part number cannot be marked on one line, it will
be carried over to the next line, thus limiting the number of available
characters for customer-specific information.
DS20001191U-page 16
2010-2021 Microchip Technology Inc. and its subsidiaries
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DS20001191U-page 17
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