ATSHA204 ATMEL [ATMEL Corporation], ATSHA204 Datasheet - Page 54

• Manufacturer Part Number: ATSHA204
• Description: Atmel CryptoAuthentication
• Manufacturer: ATMEL [ATMEL Corporation]

8.13
UpdateExtra Command
This command is used to update the values of the two “extra” bytes within the configuration zone (location 84 and 85) after the
configuration zone has been locked.
If the mode parameter indicates UserExtra at address 84:
If the mode parameter indicates selector at address 85:
Table 8-35. Input Parameters
Table 8-36. Output Parameter
Opode
Param1
Param2
Data
Name
Success
If the current value in UserExtra (byte 84 of configuration zone) is zero, then UpdateExtra writes this byte with the LS byte
of NewValue and returns success.
If the current value in UserExtra is non-zero, the command returns an execution error.
If SelectorMode (byte 19 of the configuration zone) is non-zero and Selector (byte 85 of the configuration zone) is zero,
this command will write Selector with the LS byte of NewValue and return success. Once written to a non-zero value, it is
then locked against further updating.
If SelectorMode has a value of zero, indicating that no check of the current Selector should be made, this command
always updates Selector and always succeeds.
Name
UPDATEEXTRA
Mode
NewValue
-
Size
1
Size
1
1
2
0
Notes
If the memory byte was updated, this command returns a value of 0x00
Otherwise, it returns an Execution error.
Notes
0x20
Bit 0: If zero, update config byte 84.
Bits1-7: Must be zero
LSB: Value to optionally be written to location 84 or 85 in configuration zone.
MSB: Must be 0x00.
-
If one, update config byte 85.
Atmel ATSHA204 [DATASHEET]
8740D−CRYPTO−3/12
54