Datasheet

14
AVR068
2591C-AVR-06/06
Table 5-30. Answer format
Field Size Values Description
Answer ID 1 byte CMD_READ_FUSE_ISP Answer id
Status1 1 byte STATUS_CMD_OK
A status value indicating the result
of the operation, always OK
data 1 byte The fuse byte read from the device
Status2 1 byte STATUS_CMD_OK
A status value indicating the result
of the operation, always OK
5.2.10 CMD_PROGRAM_LOCK_ISP
See CMD_PROGRAM_FUSE. This command is basically the same as the program
fuse command, only that ISP commands for programming the lock byte must be
supplied.
5.2.11 CMD_READ_LOCK_ISP
See CMD_READ_FUSE. This command is basically the same as the read fuse
command, only that ISP commands for reading the lock byte must be supplied.
5.2.12 CMD_READ_SIGNATURE_ISP
See CMD_READ_FUSE. This command is basically the same as the read fuse
command, only that ISP commands for reading one of the signature bytes must be
supplied.
5.2.13 CMD_READ_OSCCAL_ISP
See CMD_READ_FUSE. This command is basically the same as the read fuse
command, only that ISP commands for reading the OSCCAL byte must be supplied.
5.2.14 CMD_SPI_MULTI
This is a generic command that can be used to execute any of the ISP commands.
The command writes a number of bytes to the SPI bus, and returns a number of
bytes.
Table 5-31. Command format
Field Size Values Description
Command ID 1 byte CMD_SPI_MULTI Command id
NumTx 1 byte 0-255 Number of bytes to transmit
NumRx 1 byte 0-255 Number of bytes to receive
RxStartAddr 1 byte
Start address of returned data.
Specifies on what transmitted byte
the response is to be stored and
returned.
TxData
0-255
bytes
The data be transmitted. The size
is specified by NumTx
If the number of bytes to receive is greater than number of bytes to transmit, then the
firmware will pad with the necessary 0x00 bytes. This is in order to save time-
consuming transfer from PC to the programmer.