x40620 Intersil Corporation, x40620 Datasheet - Page 8

• Manufacturer Part Number: x40620
• Description: Dual Voltage Cpu Supervisor With 64k Serial Eeprom
• Manufacturer: Intersil Corporation

Figure 9. Memory Array Programming
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.
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
SDA
S
Command
Write
(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.
Data 0
Data ACK Polling Sequence
Command Code
Enter Ack Polling
Write Sequence
Characteristics subject to change without notice.
• • •
Returned
Issue Start
Issue New
Completed
Proceed
ACK
YES
?
Data 63
NO
S
Data ACK
Wait t
Polling
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