The Atmel? AT93C56B/66B provides 2，048/4，096 bits of Serial Electrically Erasable Programmable Read-Only Memory （EEPROM） organized as 128/256 words of 16 bits each （when the ORG pin is connected to VCC） and 256/512 words of 8 bits each （when the ORG pin is tied to ground）。 The device is optimized for use in many industrial and commercial applications where low-power and lowvoltage operations are essential. The AT93C56B/66B is available in space-saving 8-lead JEDEC SOIC， 8-lead TSSOP， 8-pad UDFN， 8-pad XDFN， and 8-ball VFBGA packages. The AT93C56B/66B is enabled through the Chip Select pin （CS） and accessed via a 3-wire serial interface consisting of Data Input （DI）， Data Output （DO）， and Shift Clock （SK）。 Upon receiving a Read instruction at DI， the address is decoded， and the data is clocked out serially on the DO pin. The write cycle is completely self-timed， and no separate erase cycle is required before Write. The write cycle is only enabled when the part is in the Erase/Write Enable state. When CS is brought high following the initiation of a write cycle， the DO pin outputs the Ready/Busy status of the part. The AT93C56B/66B operates from 1.7V to 5.5V.