X40620 Datasheet, PDF (8/17 Pages) Xicor Inc. – Dual Voltage CPU Supervisor with 64K Serial EEPROM

X40620
PROGRAM OPERATIONS
Memory Array Programming
The memory array program mode requires issuing the 8-bit
Write command followed by the address and then the data
bytes transferred as illustrated in Figure 9. Up to 64 bytes
(or more) may be transferred. Sending more than 64
bytes results in data wrapping and over-writing previ-
ous data. After the last byte to be transferred is
acknowledged a stop condition is issued which starts
the nonvolatile write cycle.
Figure 9. Memory Array Programming
SDA _S
Write
Command
Data 0
Data 63
Wait t_WC
•••
S Data ACK
Polling
ACK Polling
Once a stop condition is issued to indicate the end of
the host’s write sequence, the X40620 initiates the
internal nonvolatile write cycle. In order to take advan-
tage of the typical 5ms write cycle, ACK polling can
begin immediately. This involves issuing the start con-
dition followed by the new command code of 8 bits (1st
byte of the protocol.) If the X40620 is still busy with the
nonvolatile write operation, it will issue a “no-ACK” in
response. If the nonvolatile write operation has com-
pleted, an “ACK” will be returned and the host can then
proceed with the rest of the protocol.
Data ACK Polling Sequence
Write Sequence
Completed
Enter Ack Polling
Issue Start
Issue New
Command Code
ACK
NO
Returned?
YES
Proceed
Characteristics subject to change without notice. 8 of 17