# Atmel EDBG-based Tools Protocols
SPI programming protocol commands

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### SPI Read Fuse

Reads fuses using SPI programming

Table 158. SPI Read Fuse command format

Field | Size | Description
--- | --- | ---
SPI_CMD_READ_FUSE | 1 byte | Command ID
RetAddr | 1 byte | XML: pollIndex. Return address
cmd1 | 1 byte | Command Byte # 1 to be transmitted
cmd2 | 1 byte | Command Byte # 2 to be transmitted
cmd3 | 1 byte | Command Byte # 3 to be transmitted
cmd4 | 1 byte | Command Byte # 4 to be transmitted

Note: RetAddr indicates which of the transmitted bytes on the SPI interface contains the return value, since the SPI interface is implemented as a ring buffer (one byte in, one byte out)

Response:

Table 159. SPI Read Fuse response

Field | Size | Description
--- | --- | ---
SPI_CMD_READ_FUSE | 1 byte | Command ID
Status1 | 1 byte | SPI_STATUS_CMD_OK
Data | 1 byte | Data read from the device
Status2 | 1 byte | SPI_STATUS_CMD_OK or SPI_STATUS_RDY_BSY_TOUT

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