8.2 Command Set
The command set of CryptoMemory® is expanded compared to that of a Serial EEPROM, as the functionality of CryptoMemory exceeds that of a simple memory device. Each instruction sent to the CryptoMemory must contain four bytes:
- Command
- Address 1
- Address 2
- N
The N byte defines the number of additional data bytes to be sent or received from the CryptoMemory device. In addition, the Random Read command is available. It is the only single-byte command, but it must be preceded by an aborted write command to set up the read address.
| Command Description | Command | Addr 1 | Addr 2 | N | Data(N) | |
|---|---|---|---|---|---|---|
| Write User Zone | Normal (AT88SC0104CA-AT88SC0808CA) | $B0 | Addr | Addr | N ≤ $10 | N bytes |
| With Anti-Tearing (All Devices) | $B0 | Addr | Addr | N ≤ $08 | N bytes | |
| Random Read | Random Read | $B1 | Details on Command Usage Below | |||
|
Read User Zone | Normal Read | $B2 | Addr | Addr | N | N bytes |
| System Write | Write Config Zone (AT88SC0104CA-AT88SC0808CA) | $B4 | $00 | Addr | N | N bytes |
| Write Fuses | $B4 | $01 | Fuse ID | N ≤ $10 | ||
| Send Checksum | $B4 | $02 | $00 | $00 | 2 bytes | |
| Set User Zone | $B4 | $03 | Zone | $02 | ||
| Write Config Zone with Anti-Tearing | $B4 | $08 | Addr | $00 | N bytes | |
| Set User Zone with Anti-Tearing | $B4 | $0B | Zone | N ≤ $08 | ||
| System Read | Read Conifg Zone | $B6 | $00 | Addr | N | |
| Read Fuse Byte | $B6 | $01 | $00 | $01 | ||
| Read Checksum | $B6 | $02 | $00 | $02 | ||
| Verify Crypto | Verify Authentication | $B8 | $0X | $00 | $10 |
8 random bytes + 8 challenge bytes X = key set (0-3) |
| Verify Encryption | $B8 | $1X | $00 | $10 |
8 random bytes + 8 challenge bytes X = key set (0-3) | |
| Verify Password | Write Password | $BA | $0X | $00 | $03 |
3-byte password X = password set (0-7) |
| Read Password | $BA | $1X | $00 | $03 |
3-byte password X = password set (0-7) | |