AK9844A Datasheet, PDF (8/17 Pages) Asahi Kasei Microsystems – 4Kbit EEPROM with 4ch 8bit D/A Converter

ASAHI KASEI
[AK9844A]
Instruction Set
The AK9844A has 6 instructions such as READ, WRITE, WREN, WRDS, PDEN, PDDS. Each
instruction consists of Op-code, address and data. The instruction set is showed on Table 6.
When the instructions are executed consecutively, the CS pin should be brought to high level for a
minimum of 250ns(tCS) between consecutive instruction cycle.
Instruction Op-code
Address
Data
Comments
READ
WRITE
WREN
WRDS
PDEN
PDDS
1010100
1010010
1010001
1010000
1010110
1010011
A8 A7 A6 A5 A4 A3 A2 A1 A0
A8 A7 A6 A5 A4 A3 A2 A1 A0
1 XXXXXXXX
0 XXXXXXXX
0 XXXXXXXX
0 XXXXXXXX
D15-D0
D15-D0
X
X
X
X
Read register
Write register
Write enable
Write disable
Power down enable
Power down disable
Table 6. Instruction set
X: Don't care
„ 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 DO in, the AK9844A will be put into the automatic write time-out
period. During the automatic write time-out period (Busy status), the CS pin need not be high level.
The DO pin indicates the Ready/Busy status of the EEPROM in AK9844A. After the 32nd rising
edge of SK to read DO in, the AK9844A will be put into the automatic write time-out period. When
the automatic write time-out period start, the DO pin outputs the Ready/Busy status. When the DO
pin outputs low level, the AK9844A is in the automatic write time-out and the next instruction can not
be accepted. When the DO pin outputs high level, the automatic write time-out period has ended
and the AK9844A is ready for a next instruction.
When the CS pin is changed to high level after confirmation of Ready/Busy signal on the DO pin,
the DO pin becomes "Hi-Z". The Ready/Busy signal can be confirmed until the initial 1 bit of the
next instruction inputs from the execution of the WRITE instruction.
CS
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
31 32
SK
DI
1 0 1 0 0 1 0 A8 A7 A6 A5 A4 A3 A2 A1 A0 D15 D14 D13
D1 D0
DO
Hi-Z
Status output (READY),
if previous instruction is WRITE.
WRITE instruction
BUSY
READY
tE/W
DAD05E-00
-8-
2005/03