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X46402
Characteristics subject to change without notice.
9 of 23
Figure 9. Definition of Start and Stop Conditions
Acknowledge
Acknowledge is a software convention used to indicate
successful data transfer. The transmitting device,
either master or slave, will release the bus after trans-
mitting eight bits. During the ninth clock cycle the
receiver will pull the SDA line LOW to acknowledge
that it received the eight bits of data.
The X46402 will respond with an acknowledge after
recognition of a start condition and its slave address. If
both the device and a write condition have been
selected, the X46402 will respond with an acknowledge
after the receipt of each subsequent eight-bit word.
Reset Device Command
The Reset Device command resets the tamper bit,
clears the tamper counter and removes the tamper
“l(fā)ock” (allowing the device to accept commands). How-
ever, the Reset Device command does not clear any
memory array area.
SCL
SDA
Start Condition
Stop Condition
Table 3. X46402 Instruction Set
Notes:
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.
1st Byte
After Start
1000 0000
1000 1000
1001 0000
1001 1000
1010 0000
1010 1000
1011 0000
1011 1000
1100 0000
1100 1000
1101 1000
1110 1000
1111 0000
1st Byte
After
Password
High Address
High Address
High Address
High Address
0000 0000
0000 0000
0000 0000
0000 0000
0000 0000
High Address
High Address
not used
not used
All the rest
2nd Byte
After
Password
Low address
Low address
Low address
Low address
0000 0000
0000 0000
0000 0000
0000 0000
0000 0000
Low address
Low address
not used
not used
Command Description
Password Memory Array Read
OTP Read
Password Memory Array Write
OTP Write
Change Memory Read Password
Change OTP Read Password
Change Memory Write Password
Change OTP Write Password
Change Reset Password
No-Password Memory Array Read
No-Password Memory Array Write
Reset Device Command (Resets Tamper bit)
ACK Polling command (Ends Password operation)
Reserved
Password Used
Memory Read
OTP Read
Memory Write
OTP Write
Memory Read
OTP Read
Memory Write
OTP Write
Reset
None
None
Reset
None