AT88SC0104CA_11 ATMEL [ATMEL Corporation], AT88SC0104CA_11 Datasheet - Page 51

• Manufacturer Part Number: AT88SC0104CA_11
• Description: Atmel CryptoMemory Specification Datasheet
• Manufacturer: ATMEL [ATMEL Corporation]

10.8
10.8.1 Functional
10.8.2 Read Config Zone
10.8.3 Read Fuse Byte
System READ: $B6
Figure 10-5. System READ Command Functional Description
The System Read command allows reading of the system data from the device. Depending on the value of the P1 parameter,
the host may read the data in the configuration memory, the fuses, or a checksum.
Table 10-9. System READ Command Detail
To read 256 bytes, the host should set N = $00. This is true for any outgoing command, and is defined by ISO 7816-3. If the
address provided at P2 is an unauthorized address, the device will return the "Command Unauthorized" code ($69 $00) after it
has received the header. Since access rights vary throughout the configuration zone, the host may provide an authorized
starting address, but a number of bytes N that causes the device to reach unauthorized data. In this case, the device will
transmit the authorized bytes, but unauthorized bytes will be replaced by the "fuse byte" (see below). At the end of this
command the "Command Unauthorized" code ($69 $00) will be returned instead of $90 $00 to indicate that some of the bytes
returned are not valid
Fuse data is returned in the form of a single byte. Bits 0 to 3 represent the fuse states; a value of ‘0’ indicates the fuse has
been blown. Bits 4 to 7 are not used as security fuses and are reserved by Atmel.
Table 10-10. Fuse Byte Definition
Command
Read Config Zone
Read Fuse Byte
Read Checksum
resv
F
7
Host
Read Command
Address 1
Address 2
Number of bytes N
resv
F
6
resv
F
5
Device
Data
…
Data
Atmel AT88SC0104CA/0204CA/0404CA/0808CA [Datasheet]
resv
F
4
CLA
$00
$00
$00
SEC
INS
$B6
$B6
$B6
F
N data bytes
3
$00
$01
$02
P1
PER
F
2
addr
$00
$00
P2
CMA
8664E−CRYPTO−12/11
F
1
$01
$02
P3
N
Data (N)
FAB
F
0
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