
AT88RF1354 SPI User Guide For CryptoRF
1.4.2
ACK/NACK Response Byte
The first byte of each response is usually an ACK/NACK byte which indicates if the requested
operation succeeded or failed. The bit definitions for the ACK/NACK byte are shown in Figure 4
and Figure 5. This response byte contains 6 bits from the Error Register, and 2 bits which indicate
the success or failure of the requested operation. 01b in the least significant bits is an ACK,
indicating success. 10b in the least significant bits is a NACK, indicating failure. The contents of
the error register are not relevant to non-RF commands and can be ignored.
Figure 4.
ACK/NACK Byte Format for ACK Response
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
CRC
FRAME
BYTE
TIME
COL
SPE
0 b
1 b
Error Register Bits
ACK
Figure 5.
ACK/NACK Byte Format for NACK Response
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
CRC
FRAME
BYTE
TIME
COL
SPE
1 b
0 b
Error Register Bits
NACK
The three RF communication commands Poll Continuous, Poll Single, and TX Data return the
Error Register contents in the first byte of the response. Figure 6 shows the Error Register
format.
Figure 6.
Error Register Format in RF Command Responses
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
CRC
FRAME
BYTE
TIME
COL
SPE
0 b
0 b
1-6
8586A—RFID—5/09