Turbo IC, Inc.
24C01/24C02
PRODUCT INTRODUCTION
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 I²C 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
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.
2
ETC [ ETC ]
