at88sc153 ATMEL Corporation, at88sc153 Datasheet - Page 12

• Manufacturer Part Number: at88sc153
• Description: 3 X 64 X 8 Secure Memory With Authentication
• Manufacturer: ATMEL Corporation

9.3
9.4
9.5
12
Read Fuses
Write Fuses
Answer-to-reset
AT88SC153
Figure 9-3.
Note:
The Read Fuses operation is always allowed. The AT88SC153 will continuously transmit the
fuse byte if the host continues to transmit an ACK. The command is terminated when the host
transmits a NACK and STOP bit.
Figure 9-4.
Note:
The Write Fuses operation is only allowed under secure code control; no data byte is transmitted
by the host. The fuses are blown sequentially: CMA is blown if FAB is equal to “0”, and PER is
blown if CMA is equal to “0”. If the fuses are all “0”s, the operation is canceled and the device
waits for a new command.
Once a stop condition is issued to indicate the end of the host’s write operation, the device ini-
tiates the internal nonvolatile write cycle. An ACK polling sequence can be initiated immediately.
If RST is high during SCL clock pulse, the reset operation occurs according to the ISO 7816-10
synchronous answer-to-reset. The four bytes of the answer-to-reset register are transmitted
least significant bit first, on the 32 clock pulses provided on SCL.
The values programmed by Atmel are shown in
F
F
nnn = 001 : Blow FAB
nnn = 010 : Blow CMA
nnn = 100 : Blow PER
x
x
= 1: fuse is not blown
= 0: fuse is blown
Read Fuses
Write Fuses
R
S
T
A
T
Figure 9-5
below.
0
S
O
P
T
1016E–SMEM–12/07