ASAHI KASEI

[AK6480C/81]

DAS04E-00

2005/03

- 2 -

General Description

The AK6480C/81C is a 8192bit, serial, read/write, non-volatile memory device fabricated using an

advanced CMOS EEPROM technology.

The AK6480C/81C has 8192bits of memory organized

into 512 registers of 16 bits each.

The AK6480C/81C can operate full function under wide

operating voltage range from 1.8V to 5.5V.

The charge up circuit is integrated for high voltage

generation that is used for write operation.

The AK6480C/81C can connect to the serial communication port of popular one chip

microcomputer directly (3 line negative clock synchronous interface).

At write operation,

AK6480C/81C takes in the write data from data input pin (DI) to a register synchronously with

rising edge of input pulse of serial clock pin ( SK ).

And at read operation, AK6480C/81C takes

out the read data from a register to data output pin (DO) synchronously with falling edge of SK .

The AK6480C/81C has 5 instructions such as READ, WRITE, PAGE WRITE, WREN (write enable)

and WRDS (write disable). Each instruction is organized by op-code block (8bits), address block

(8bits) and data (8bits x 2).

When input level of SK pin is high level and input level of chip

select ( CS ) pin is changed from high level to low level, AK6480C/81C can receive the

instructions.

Special features of the AK6480C/81C include : automatic write time-out with auto-ERASE,

Ready/ Busy status signal output and ultra-low standby power mode when deselected ( CS

=high).

Software and Hardware controlled write protection

The AK6480C/81C has 2 (hardware and software) write protection functions.

After power on or after execution of WRDS (write disable) instruction, execution of WRITE

instruction will be disabled.

This write protection condition continues until WREN instruction is

executed or VCC is removed from the part.

Execution of READ instruction is independent of both WREN and WRDS instructions.

Reset pin should be low level when WRITE instruction is executed.

When the Reset pin is high

level, the WRITE instruction is not executed.

Ready/ Busy status signal

During the automatic write time-out period ( Busy status), the AK6480C/81C can't accept the

other instructions. The AK6480C/81C has 2 functions to know the Busy status from exterior.

The RDY/ BUSY pin indicates the Busy status regardless of the CS pin status.

The

RDY/ BUSY pin outputs the low level regardless of the CS pin status during Busy status.

Except the above status, this pin outputs high level.

Also the DO pin indicates the Busy status.

When input level of SK pin is low level and input

level of CS pin is changed from high level to low level, the AK6480C/81C is in the status output

mode and the DO pin indicates the Ready/ Busy status.

The Ready/ Busy status outputs on

DO pin until CS pin is changed from low level to high level, or first bit ("1") of op-code of next

instruction is given to the part.

Except when the device is in the status output mode or outputs

data, the DO pin is in the high impedance state.