X76F100 Datasheet, PDF (4/17 Pages) Xicor Inc. – 1K 128 x 8 Bit

X76F100
Figure 2. Data Validity
SCL
SDA
Data Stable
Data
Change
Figure 3. Definition of Start and Stop Conditions
SCL
SDA
Start Condition
Table 1. X76F100 Instruction Set
Command after Start
1 0 0 S₃ S₂ S₁ S₀0
1 0 0 S₃ S₂ S₁ S₀ 1
11111100
11111110
01010101
Stop Condition
Command Description
Sector Write
Sector Read
Change Write Password
Change Read Password
Password ACK Command
Password Used
Write
Read
Write
Write
None
Illegal command codes will be disregarded. The part
will respond with a “no-ACK” to the illegal byte and
then return to the standby mode. All write/read opera-
tions require a password.
PROGRAM OPERATIONS
Sector Write
The sector write mode requires issuing the 8-bit write
command followed by the password and then the data
bytes transferred as illustrated in Figure 4. The write
command byte contains the address of the sector to be
written. Data is written starting at the first address of a
sector and eight bytes must be transferred. After the
last byte to be transferred is acknowledged a stop con-
dition is issued which starts the nonvolatile write cycle.
If more or less than 8-bytes are transferred, the data in
the sector remains unchanged.
ACK Polling
Once a stop condition is issued to indicate the end of
the host’s write sequence, the X76F100 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 X76F100 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.
REV 1.0 6/22/00
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