ASAHI KASEI

[AK9844]

DAD02E-00

1999/05

- 4 -

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„ 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"

PROTECT ="L"

Programming State

Enable

Disable

Enable

Disable

Memory Block

{

Õ

{

Õ

DAC Register Block

{

ÕÕ

Õ

{ :Programming into the block is executed.

Õ :Programming into the block is not executed.

Table.1 Relation between the programming operation and the PROTECT pin