HN58X2402 Datasheet, PDF (15/21 Pages) Hitachi Semiconductor – Two-wire serial interface 2k / 4k / 8k / 16k / 32k / 64k EEPROM(8-kword x 8-bit)

HN58X2402/58X2404/58X2408/58X2416/58X2432/58X2464
Read Operation
There are three read operations: current address read, random read, and sequential read. Read operations are
initiated the same way as write operations with the exception of R/W = “1”.
Current Address Read:
The internal address counter maintains the last address accessed during the last read or write operation,
with incremented by one. Current address read accesses the address kept by the internal address counter.
After receiving a start condition and the device address word(R/W is “1”), the EEPROM outputs the 8-bit
current address data from the most significant bit following acknowledgment “0” If the EEPROM receives
acknowledgment “1” (no acknowledgment) and a following stop condition, the EEPROM stops the read
operation and is turned to a standby state. In case the EEPROM have accessed the last address of the last
page at previous read operation, the current address will roll over and returns to zero address. In case the
EEPROM have accessed the last address of the page at previous write operation, the current address will
roll over within page addressing and returns to the first address in the same page. The current address is
valid while power is on. The current address after power on will be indefinite. The random read operation
described below is necessary to define the memory address.
Current Address Read Operation
2k to 64k
Device
address
1010
Read data (n+1)
R
Start
ACK No ACK
R/W
Notes: 1. Don‘t care bit for 16k.
2. Don‘t care bits for 8k and 16k.
3. Don‘t care bits for 4k, 8k and 16k.
Stop
Random Read:
This is a read operation with defined read address. A random read requires a dummy write to set read
address. The EEPROM receives a start condition, device address word(R/W=0) and memory address (8-bit
for 2kbit to 16kbit EEPROMs, 2 × 8-bit for 32kbit and 64kbit EEPROMs) sequentially. The EEPROM
outputs acknowledgment “0” after receiving memory address then enters a current address read with
receiving a start condition. The EEPROM outputs the read data of the address which was defined in the
dummy write operation. After receiving acknowledgment “1”(no acknowledgment) and a following stop
condition, the EEPROM stops the random read operation and returns to a standby state.
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