4.3.1.1 Opcode Field

The opcode is a 4-bit field in the first word of the response. The opcode indicates how the command was processed (see Table 4-11). If the command was processed successfully, the response opcode is PASS. If there was an error in processing the command, the response opcode is FAIL and the QE_Code indicates the reason for the failure. If the command sent to the Programming Executive is not identified, the Programming Executive returns a NACK response.