at24cs128 ATMEL Corporation, at24cs128 Datasheet - Page 8

• Manufacturer Part Number: at24cs128
• Description: 2-wire Serial Eeproms With Permanent Software Write Protect
• Manufacturer: ATMEL Corporation

RANDOM READ: A random read requires a “dummy” byte
write sequence to load in the data word address. Once the
device address word and data word address are clocked in
and acknowledged by the EEPROM, the microcontroller
must generate another start condition. The microcontroller
now initiates a current address read by sending a device
address with the read/write select bit high. The EEPROM
acknowledges the device address and serially clocks out
the data word. The microcontroller does not respond with a
zero but does generate a following stop condition (refer to
Figure 5).
Figure 1. Device Address
Figure 2. Byte Write
Figure 3. Page Write
(* = DON’T CARE bit)
(† = DON’T CARE bit for the 128K)
8
AT24CS128/256
SEQUENTIAL READ: Sequential reads are initiated by
either a current address read or a random address read.
After the microcontroller receives a data word, it responds
with an acknowledge. As long as the EEPROM receives an
acknowledge, it will continue to increment the data word
address and serially clock out sequential data words. When
the memory address limit is reached, the data word
address will “roll over” and the sequential read will con-
tinue. The sequential read operation is terminated when
the microcontroller does not respond with a zero but does
generate a following stop condition (refer to Figure 6).