S-25C010A/020A/040A

Seiko Instruments Inc.

9

Pin Functions

This is an input pin to set a chip in the select status. In the “H” input level, the device is in the non-select status and its

output is high impedance. The device is in standby as long as it is not in Write inside. The device goes in active by

setting the chip select to “L”. Input any instruction code after power-on and a falling of chip select.

2. SI (Serial data input ) pin

This pin is to input serial data. This pin receives an instruction code, an address and Write data. This pin latches data at

rising edge of serial clock.

3. SO (Serial data output ) pin

This pin is to output serial data. The data output changes at falling edge of serial clock.

4. SCK (Serial clock input ) pin

This is a clock input pin to set the timing of serial data. An instruction code, an address and Write data are received at a

rising edge of clock. Data is output at falling edge of clock.

This is an input pin to protect memory data when Write instruction (WRITE, WRSR) is being input. By setting this pin to

“L”, the WEL bit in the status register is set to “L”. Therefore S-25C010A/020A/040A does not Write to the E

however, it accepts other instructions. Fix this pin “H” or “L” not to set it in the floating state.

Refer to “ Protect Operation” for details.

6.

HOLD (HOLD input ) pin

This pin is used to pause serial communications without setting the device in the non-select status.

In the hold status, the serial output goes in high impedance, the serial input and the serial clock go in “Don’t care”.

During the hold operation, be sure to set the device in active by setting the chip select ( CS pin) to “L”.

Refer to “ Hold Operation” for details.