AK6480C Datasheet, PDF (6/15 Pages) Asahi Kasei Microsystems – 8Kbit Serial CMOS EEPROM

ASAHI KASEI
[AK6480C/81]
Write
The write instruction is followed by 16 bits of data to be written into the specified address. After
the 32nd rising edge of SK to read D0 in, the AK6480C/81C will be put into the automatic write
time-out period. During the automatic write time-out period ( Busy status) and while entering
write instruction, the RESET pin should be low level. If the RESET pin is set to high level during
the automatic write time-out period, the AK6480C/81C 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 pin should be set to high
level. When the RESET pin is kept at high level, the write is not executed. This becomes write
protection function.
The CS pin need not be high level during automatic write time-out period ( Busy status).
RESET
CS
SK
DI
DO
RDY/
BUSY
1 2 3 4 5 6 7 8 9 10
1 0 1 0 0 1 0 A8 A7 A6
Hi-Z
15 16 17 18
A1 A0 D15 D14
WRITE (AK6480C)
30 31 32
D2 D1 D0
tE/W
RESET
CS
SK
DI
DO
RDY/
BUSY
1 2 3 4 5 6 7 8 9 10
1 0 1 0 0 1 0 A0 A1 A2
Hi-Z
15 16 17 18
A7 A8 D0 D1
WRITE (AK6481C)
30 31 32
D13 D14 D15
tE/W
Page Write
AK6480C/81C has Page Write mode, which can write the data within 8 words with one
programming cycle. The input data sent to the shift register within 8 words. After the instruction
input, the internal programming cycle starts when CS pin changes low to high. After the
instructions are inputted, CS pin should change low to high after the last data bit (D0,
AK6481C: D15) inputs and before next SCK clock rises. Page Write function can start only at this
timing.
After the receipt of each word, the three lower order address pointer bits internally incremented by
one. The higher order seven bits of the word address remains constant. When the highest
address is reached ”XX XXXX X111”, the address counter rolls over to address ”XX XXXX X000”
allowing the page write cycle to be continued indefinitely.
If AK6480C/81C is transmitted more than 8 words, the address counter will ”roll over” and the
previously written data will be overwritten. When AK6480C/81C is transmitted 10 words, ninth
word will be overwritten to first word, and tenth word will be overwritten to second word.
During the automatic write time-out period ( Busy status) and while entering Page Write
DAS04E-00
-6-
2005/03