AT88SC0204CA_14 Datasheet, PDF (36/71 Pages) ATMEL Corporation – Atmel CryptoMemory

8.11 System Read: $B6
8.11.1 Functional
Figure 8-13. System Read Command Functional Description
Host
Device
Read Command
Address 1
Address 2
Number of bytes N
Data
…
Data
N data bytes
The system read command allows reading of system data from the device. Depending on the value of Address 1, the host may
read the data in the Configuration zone, or the fuses.
Table 8-6. Zone Configuration Example
Command Description
Read Config Zone
Read Fuse Byte
Read Checksum
Command
Addr 1
Addr 2
N
$B6
$00
Addr
N
$B6
$01
$00
$01
$B6
$02
$00
$02
8.11.2 Read Config Zone
The data byte address to be read is defined by Address 2 in the command and is internally incremented following the
transmission of each data byte. The value N defines how many bytes CryptoMemory will read, a value of zero will result in
256 bytes read. If the address provided is an unauthorized address, the device will not ACK the N byte and will not return any
data. Since access rights vary throughout the Configuration zone, the host may provide an authorized starting address and a
number of bytes N that causes the device to reach unauthorized data. In this case the device will transmit the fuse byte (see
below) in place of unauthorized bytes.
8.11.3 Read Fuse Byte
Fuse data is returned in the form of a single byte. Bits zero to three represent the fuse states; a value of zero indicates the
fuse has been blown. Bits four to seven are not used as security fuses and are reserved by Atmel.
Table 8-7. Fuse Byte Definition
F7
resv
F6
resv
F5
resv
F4
resv
F3
SEC
F2
PER
F1
CMA
F0
FAB
 
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AT88SC0104CA/0204CA/0404CA/0808CA [Datasheet]
Atmel-8664F-CryptoMem-Low-Density-Full-Specification-Datasheet_022014