AK9844 Datasheet, PDF (4/17 Pages) Asahi Kasei Microsystems – 4Kbit EEPROM with 4ch 8bit D/A Converter

ASAHI KASEI
[AK9844]
„ Data Protection
To protect against accidental data disturb, the AK9844 has programming enable state and programming
disable state. In programming disable state, the programming operation is not executed.
When Vcc is applied to the AK9844, the AK9844 is powered up in the programming disable mode. The
programming instruction should be preceded by the WREN instruction. Once the WREN instruction is
executed, the programming state remains enabled until the WRDS instruction is executed or VCC is removed
from the device. Execution of the READ instruction is independent of both WREN and WRDS instructions.
The AK9844 also can prohibit to program into the DAC register block by the control of the PROTECT pin.
When the PROTECT pin is "L", the programming into the DAC register block is not executed.
PROTECT pin
PROTECT ="H"
Programming State
Enable
Disable
Memory Block
{
Õ
DAC Register Block
{
Õ
{ :Programming into the block is executed.
Õ :Programming into the block is not executed.
PROTECT ="L"
Enable
Disable
{
Õ
Õ
Õ
Table.1 Relation between the programming operation and the PROTECT pin
DAD02E-00
-4-
1999/05