AK6420A-1 Datasheet, PDF (4/15 Pages) Asahi Kasei Microsystems – 2K / 4K / 8Kbit Serial CMOS EEPROM

ASAHI KASEI
„ Pin Description
[AK6420A/40A/80A]
CS (Chip Select)
When SK is high level and CS is changed from high level to low level, AK6420A/40A/80A can receive the
instructions. CS should be kept low level while receiving op-code, address and data and while outputting data.
If CS is changed to high level during the above period, AK6420A/40A/80A stops the instruction execution.
When SK is low and CS is changed from high level to low level, AK6420A/40A/80A will be in status output
mode. The CS need not be low level during the automatic write time-out period (BUSY status).
SK (Serial Clock)
The SK clock pin is the synchronous clock input for input/output data. At write operation, AK6420A/40A/80A
takes in the write data from data input pin (DI) synchronously with rising edge of input pulse of serial clock pin
(SK). And at read operation, AK6420A/40A/80A takes out the read data to data output pin (DO)
synchronously with falling edge of SK. The SK clock is not needed during the automatic write time-out period
(BUSY status), the status output period and when the device isn't selected (CS = high level).
DI (Data Input)
The op-code, address and write data is input to the DI pin.
DO (Data Output)
The DO pin outputs the read data and status signal and will be high impedance except for this timing.
RDY/BUSY (Ready/Busy status)
This pin outputs the internal programming status. When the AK6420A/40A/80A is in the automatic write time-
out period, this pin outputs the low level (BUSY status), and outputs the high level except for this timing.
RESET (Reset)
The AK6420A/40A/80A stops executing the write instruction when the RESET pin is high level. The RESET
pin should be low level while the write instruction input period and the automatic write time-out period. If the
RESET pin is high level while the automatic write time-out period, the AK6420A/40A/80A stops execution of
internal programming and the device returns to ready status. In this case the word data of the specified
address will be incomplete. When inputting the new instruction after RESET, the CS should be set to high
level. The read, write enable and write disable instructions are not affected by RESET pin status.
Vcc (Power Supply)
GND (Ground)
DAS01E-00
-4-
1999/05