CMOS IC 2-WIRE BUS
1K/2K ELECTRICALLY ERASABLE PROGRAMMABLE ROM
128/256 X 8 BIT EEPROM
Turbo IC, Inc.
24C01/24C02
PRODUCT INTRODUCTION
PIN DESCRIPTION
DESCRIPTION:
The Turbo IC 24C01/24C02 is a serial 1K/2K EEPROM
fabricated with Turbo's proprietary, high reliability, high per-
formance CMOS technology. It's 1K/2K of memory is orga-
nized as 128/256 x 8 bits. The memory is configured as 16/
32 pages with each page containing 8 bytes. This device
offers significant advantages in low power applications.
The Turbo IC 24C01/24C02 uses the IC addressing proto-
col and 2-wire serial interface which includes a bidirec-
tional serial data bus synchronized by a clock. It offers a
flexible byte write and a faster 8-byte page write.
The Turbo IC 24C01/24C02 is assembled in either a 8-pin
PDIP or 8-pin SOIC package. Pin #1 is the A0 device ad-
dress input for the device. Pin #2 is the A1 device address
input for the device. Pin #3 is the A2 device address input
for the device, such that a total of eight 24C01/24C02 de-
vices can be connected on a single bus. Pin #4 is the ground
(Vss). Pin #5 is the serial data (SDA) pin used for bidirec-
tional transfer of data. Pin #6 is the serial clock (SCL) input
pin. Pin #7 is the write protect (WP) pin used to protect hard-
ware data. Pin #8 is the power supply (Vcc) pin.
All data is serially transmitted in bytes (8 bits) on the SDA
bus. To access the Turbo IC 24C01/24C02 (slave) for a read
or write operation, the controller (master) issues a start con-
dition by pulling SDA from high to low while SCL is high. The
master then issues the device address byte which consists
of 1010 (A2) (A1) (A0) (R/W). The most significant bits (1010)
are a device type code signifying an EEPROM device. A0,
A1, and A2 are the device address select bits which has to
match the A0, A1, and A2 pin inputs on the device. The B[7]
bit (or B[6] bit in the 24C01) is the most significant bit of the
memory address. The read/write bit determines whether to
do a read or write operation. After each byte is transmitted,
the receiver has to provide an acknowledge by pulling the
SDA bus low on the ninth clock cycle. The acknowledge is a
handshake signal to the transmitter indicating a successful
data transmission.
FEATURES :
Power Supply Voltage
Single Vcc for Read and Programming
(Vcc = 2.7 V to 5.5 V)
Low Power (Isb = 2a @ 5.5 V)
IC Bus, 2-Wire Serial Interface
Support Byte Write and Page Write (8 Bytes)
Automatic Page write Operation (maximum 10 ms)
Internal Control Timer
Internal Data Latches for 8 Bytes
High Reliability CMOS Technology with EEPROM Cell
Endurance : 1,000,000 Cycles
Data Retention : 100 Y
ears
1
SERIAL CLOCK (SCL)
The SCL input synchronizes the data on the SDA
bus. It is used in conjunction with SDA to define
the start and stop conditions. It is also used in
conjunction with SDA to transfer data to and from
the Turbo IC 24C01/24C02.
SERIAL DATA (SDA)
SDA is a bidirectional pin used to transfer data
in and out of the Turbo IC 24C01/24C02. The pin
is an open-drain output. A pullup resistor must
be connected from SDA to Vcc.
PIN DESCRIPTION
DEVICE ADDRESS (A0 & A1 & A2)
A0, A1, and A2 are device address inputs that
enables a total of eight 24C01/24C02 devices to
connect on a single bus. If the address input pin
is left unconnected, it is interpreted as zero.
WRITE PROTECT (WP)
When the write protect input is connected to Vcc,
the entire memory array is protected against write
operations. For normal write operations, the write
protect pin should be grounded. When the pin is
left unconnected, WP is interpreted as zero.
1
2
3
4
5
6
7
8
A0
A1
A2
GND
VCC
WP
SCL
SDA
8 pin PDIP
1
2
3
4
5
6
7
8
A0
A1
A2
GND
VCC
WP
SCL
SDA
8 pin SOIC
24C01/24C02
PRODUCT INTRODUCTION
Turbo IC, Inc.
Note: The write cycle time t
WC
is the time from a valid stop condition of a write sequence to the end of the internal clear / write cycle.
DESCRIPTION (Continued):
For a write operation, the master issues a start condition, a
device address byte, a memory address byte, and then up to
8 data bytes. The Turbo IC 24C01/24C02 acknowledges
after each byte transmission. To terminate the transmission,
the master issues a stop condition by pulling SDA from low
to high while SCL is high.
For a read operation, the master issues a start condition and
a device address byte. The Turbo IC 24C01/24C02 acknowl-
edges, and then transmits a data byte, which is accessed
from the EEPROM memory. The master acknowledges, indi-
cating that it requires more data bytes. The Turbo IC 24C01/
24C02 transmits more data bytes, with the memory address
counter automatically incrementing for each data byte, until
the master does not acknowledge, indicating that it is termi-
nating the transmission. The master then issues a stop con-
dition.
DEVICE OPERATION:
BIDIRECTIONAL BUS PROTOCOL:
The Turbo IC 24C01/24C02 follows the IC bus protocol. The
protocol defines any device that sends data onto the SDA
bus as a transmitter, and the receiving device as a receiver.
The device controlling the transfer is the master and the de-
vice being controlled is the slave. The master always initiates
the data transfers, and provides the clock for both transmit
and receive operations. The Turbo IC 24C01/24C02 acts as
a slave device in all applications. Either the master or the
slave can take control of the SDA bus, depending on the
requirement of the protocol.
START/STOP CONDITION AND DATA TRANSITIONS:
While SCL clock is high, a high to low transition on the SDA
bus is recognized as a START condition which precedes any
read or write operation. While SCL clock is high, a low to
high transition on the SDA bus is recognized as a STOP con-
dition which terminates the communication and places the
Turbo IC 24C01/24C02 into standby mode. All other data
transitions on the SDA bus must occur while SCL clock is
low to ensure proper operation.
ACKNOWLEDGE:
All data is serially transmitted in bytes (8 bits) on the SDA
bus. The acknowledge protocol is used as a handshake sig-
nal to indicate successful transmission of a byte of data. The
bus transmitter, either the master or the slave (Turbo IC
24C01/24C02), releases the bus after sending a byte of data
on the SDA bus. The receiver pulls the SDA bus low during
the ninth clock cycle to acknowledge the successful trans-
mission of a byte of data. If the SDA is not pulled low during
the ninth clock cycle, the Turbo IC 24C01/24C02 terminates
the data transmission and goes into standby mode.
For the write operation, the Turbo IC 24C01/24C02 acknowl-
edges after the device address byte, acknowledges after the
memory address byte, and acknowledges after each subse-
quent data byte.
For the read operation, the Turbo IC 24C01/24C02 acknowl-
edges after the device address byte. Then the Turbo IC 24C01/
24C02 transmits each subsequent data byte, and the mas-
ter acknowledges after each data byte transfer, indicating
that it requires more data bytes. The Turbo IC 24C01/24C02
monitors the SDA bus for the acknowledge. To terminate the
transmission, the master does not acknowledge, and then
sends a stop condition.
Write Cycle Timing
2
24C01/24C02
PRODUCT INTRODUCTION
Data Valid
Turbo IC, Inc.
Start and Stop Definition
Output Acknowledge
SDA
SCL
DATA STABLE
DATA STABLE
DATA
CHANGE
SDA
SCL
START
STOP
SCL
DATA IN
DATA OUT
1
8
9
ACKNOWLEDGE
START
3
24C01/24C02
PRODUCT INTRODUCTION
Turbo IC, Inc.
DEVICE ADDRESSING:
Following the start condition, the master will issue a device
address byte consisting of 1010 (A2) (A1) (A0) (R/W) to ac-
cess the selected Turbo IC 24C01/24C02 for a read or write
operation. A0, A1, and A2 are the device address select bits
which have to match the A0, A1, and A2 pin inputs on the
24C01/24C02 device. The B[7] bit (B[6] bit in the 24C01) is
the most significant bit of the memory address. The (R/W)
bit is a high (1) for read and low (0) for write. If A0, A1, or
A2 are left unconnected, the Turbo IC 24C01/24C02 device
shall interpret as V
il
input(s).
DATA INPUT DURING WRITE OPERATION:
During the write operation, the Turbo IC 24C01/24C02 latches
the SDA bus signal on the rising edge of the SCL clock.
DATA OUTPUT DURING READ OPERATION:
During the read operation, the Turbo IC 24C01/24C02 seri-
ally shifts the data onto the SDA bus on the falling edge of
the SCL clock.
MEMORY ADDRESSING:
The memory address is sent by the master in the form of 2
bytes. Device address A2, A1, and A0 is included in the first
byte. The remaining memory address bits B[7:0] are included
in the second byte of the device address of the 24C02. The
memory address byte can only be sent as part of a write
operation. On the other hand, in the 24C01, the first byte is
the same as in the 24C02; however, the second byte of the
24C01 contains remaining address bits B[6:0]. The B[7] bit
in the 24C01 is treated as a 'don't care' bit.
BYTE WRITE OPERATION:
The master initiates the byte write operation by issuing a
start condition, followed by the device address byte 1010
(A2) (A1) (A0) 0, followed by the memory address byte, fol-
lowed by one data byte, followed by an acknowledge, then a
stop condition. After each byte transfer, the Turbo IC 24C01/
24C02 acknowledges the successful data transmission by
pulling the SDA bus low. The stop condition starts the inter-
nal EEPROM write cycle, and all inputs are disabled until the
completion of the write cycle.
4
PAGE WRITE OPERATION:
The master initiates the page write operation by issuing a
start condition, followed by the device address byte 1010
(A2) (A1) (A0) 0, followed by the memory address byte, fol-
lowed by up to 8 data bytes, followed by an acknowledge,
then a stop condition. After each byte transfer, the Turbo IC
24C01/24C02 acknowledges the successful data transmis-
sion by pulling SDA low. After each data byte transfer, the
memory address counter is automatically incremented by
one. The stop condition starts the internal EEPROM write
cycle only if the stop condition occurs in the clock cycle im-
mediately following the acknowledge (10th clock cycle). All
inputs are disabled until the completion of the write cycle.
POLLING ACKNOWLEDGE:
During the internal write cycle of a write operation in the Turbo
IC 24C01/24C02, the completion of the write cycle can be
detected by polling acknowledge. The master starts acknowl-
edge polling by issuing a start condition, then followed by the
device address byte 1010 (A2) (A1) (A0) 0. If the internal
write cycle is finished, the Turbo IC 24C01/24C02 acknowl-
edges by pulling the SDA bus low. If the internal write cycle is
still ongoing, the Turbo IC 24C01/24C02 does not acknowl-
edge because it's inputs are disabled. Therefore, the device
will not respond to any command. By using polling acknowl-
edge, the system delay for write operations can be reduced.
Otherwise, the system needs to wait for the maximum inter-
nal write cycle time, tWC, given in the spec.
POWER ON RESET:
The Turbo IC 24C01/24C02 has a Power On Reset circuit
(POR) to prevent data corruption and accidental write op-
erations during power up. On power up, the internal reset
signal is on and the Turbo IC 24C01/24C02 will not respond
to any command until the VCC voltage has reached the POR
threshold value.
24C01/24C02
PRODUCT INTRODUCTION
Turbo IC, Inc.
Device Address
Byte Write
SDA LINE
DEVICE
ADDRESS
WORD ADDRESS
DATA
S
T
O
P
A
C
K
A
C
K
M
S
B
L
S
B
R
/
W
A
C
K
S
T
A
R
T
W
R
I
T
E
Page Write
SDA LINE
DEVICE
ADDRESS
WORD ADDRESS
DATA (n)
S
T
O
P
A
C
K
A
C
K
M
S
B
L
S
B
R
/
W
A
C
K
S
T
A
R
T
W
R
I
T
E
A
C
K
//
//
DATA (n + x)
5
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