7 Write Operations

All write operations to the AT21CS01/AT21CS11 begin with the host sending a Start condition, followed by a device address byte (opcode Ah for the EEPROM and opcode Bh for the Security register) with the R/W bit set to ‘0’ followed by the memory address byte. Next, the data value(s) to be written to the device are sent. Data values must be sent in 8-bit increments to the device followed by a Stop condition. If a Stop condition is sent somewhere other than at the byte boundary, the current write operation will be aborted. The AT21CS01/AT21CS11 allows single byte writes, partial page writes, and full page writes.