The register takes out the read data to the data output pin

　　The AK6420A/40A/80A is a 2048/4096/8192bit, serial, read/write, non-volatile memory device fabricated using anadvanced CMOS EEPROM technology. The AK6420A has 2048bits of memory organized into 128 registers of 16bits each.

　　The AK6440A has 4096bits of memory organized into 256 registers of 16 bits each.

　　The AK6480A has8192bits of memory organized into 512 registers of 16 bits each. The AK6420A/40A/80A can operate full functionunder wide operating voltage range from 1.8V to 5.5V.

　　The charge up circuit is integrated for high voltage generationthat is used for write operation.The AK6420A/40A/80A can connect to the serial communication port of popular one chip microcomputer directly (3line negative clock synchronous interface).

　　At write operation, AK6420A/40A/80A takes in the write data from datainput pin (DI) to a register synchronously with rising edge of input pulse of serial clock pin (SK).

　　And at read operation,AK6420A/40A/80A takes out the read data from a register to data output pin (DO) synchronously with falling edge ofSK.The AK6420A/40A/80A has 4 instructions such as READ, WRITE, WREN (write enable) and WRDS (write disable).Each instruction is organized by op-code block (8bits), address block (8bits) and data (8bits × 2).

　　When input level ofSK pin is high level and input level of chip select (CS) pin is changed from high level to low level, AK6420A/40A/80Acan receive the instructions.