S-34C04A Datasheet, PDF (8/22 Pages) Seiko Instruments Inc – FOR DIMM SERIAL PRESENCE DETECT

2-WIRE SERIAL E²PROM FOR DIMM SERIAL PRESENCE DETECT
S-34C04A
Rev.1.0_01_U
1. Selecting function
This IC has a 4 K-bit E²PROM array. The E²PROM array is devided into two pages consisting of a lower 256-byte
page and an upper 256-byte page, which change over by the set E²PROM page address order. Each page has two
128-byte blocks. Each block can be set to write-protected by software write protect function. Page write operation up
to 16 bytes and sequential read operation are available.
Operation function is identified by DTIC. There are two types of DTIC. The E²PROM memory may be accessed using
a DTIC of "1010b", and to perform the software write protection or the page address operations a DTIC of "0110b" is
required.
All operations are inhibited to be performed during write time.
For more detail, refer to " E²PROM Operation".
2. Initialization operation after power-on
By a power-on-reset circuit, this IC initializes the internal circuit at the time of power-on. Perform the beginning (start
condition) of the instruction transmission to this IC after the initialization by the power-on-reset circuit. Regarding the
datails of power-on-reset, refer to " Reset and Initialization".
3. Start condition
Start is identified by a "H" to "L" transition of the SDA line while the SCL line is stable at "H".
Every operation begins from a start condition.
4. Stop condition
Stop is identified by a "L" to "H" transition of the SDA line while the SCL line is stable at "H".
When a device receives a stop condition during a read sequence, the read operation is interrupted, and the device
enters standby mode.
When a device receives a stop condition during a write sequence, the reception of the write data is halted, and this IC
initiates a write cycle.
VDD
V_PON
t_INIT
t_SU.STA t_HD.STA
t_SU.STO
SCL
SDA
Start condition
Figure 4 Start / Stop Conditions after Power-on
Stop condition
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