A24C02
AiT Semiconductor Inc.
www.ait-ic.com
MEMORY EEPROM
2k BITS (256 X 8) TWO-WIRE SERIAL
ACKNOWLEDGE POLLING: Once the internally timed write cycle has started and the EEPROM inputs are
disabled, acknowledge polling can be initiated. This involves sending a start condition followed by the device
address word. The read/write bit is representative of the operation desired. Only if the internal write cycle has
completed will the EEPROM respond with a "0", allowing the read or write sequence to continue.
5. Read Operations
Read operations are initiated the same way as write operations with the exception that the read/write select
bit in the device address word is set to "1". There are three read operations: current address read, random
address read and sequential read.
CURRENT ADDRESS READ: The internal data word address counter maintains the last address accessed
during the last read or write operation, incremented by one. This address stays valid between operations as
long as the chip power is maintained. The address "roll over" during read is from the last byte of the last
memory page to the first byte of the first page. The address "roll over" during write is from the last byte of the
current page to the first byte of the same page. Once the device address with the read/write select bit set to
"1" is clocked in and acknowledged by the EEPROM, the current address data word is serially clocked out.
The microcontroller does not respond with an input "0" but does generate a following stop condition (see
Figure 7 on page12).
RANDOM READ: A random read requires a "dummy" byte write sequence to load in the data word address.
Once the device address word and data word address are clocked in and acknowledged by the EEPROM, the
microcontroller must generate another start condition. The microcontroller now initiates a current address
read by sending a device address with the read/write select bit high. The EEPROM acknowledges the device
address and serially clocks out the data word. The microcontroller does not respond with a "0" but does
generate a following stop condition (see Figure 8 on page12)
SEQUENTIAL READ: Sequential reads are initiated by either a current address read or a random address
read. After the microcontroller receives a data word, it responds with an acknowledge. As long as the
EEPROM receives an acknowledge, it will continue to increment the data word address and serially clock out
sequential data words. When the memory address limit is reached, the data word address will "roll over" and
the sequential read will continue. The sequential read operation is terminated when the microcontroller does
not respond with a "0" but does generate a following stop condition (see Figure 9 on page12).
REV2.1
- SEP 2008 RELEASED, JUN 2017 UPDATED -
- 9 -
AITSEMI [ AiT Semiconductor ]
