User Guide

Table Of Contents
Format for Microprocessor Reply to Host
Overview of the Communication Protocol 39
The following shows an example of an ACK message to an Erase Flash command.
The value in the OpCode field (0x07) is the same as the Erase Flash OpCode, 0x07.
Microprocessor Fault Reply Message
If a problem occurs during the execution of a command, the microprocessor returns a
non-zero status value. Although this usually implies a fault or error, sometimes the non-
zero status simply indicates a condition of the system. For instance, when executing a
Read Tag Single command, if no tags are found, a status code of 0x0400 is returned. An
example of a fault reply message is shown for the Erase Flash command.
A list of error codes is included in
Appendix C: Error Messages. Refer to this list when
encountering any non-zero status codes.
Microprocessor Data Reply Message
If the requested command requires that the microprocessor returns data, then the
microprocessor creates a message similar to the Microprocessor ACK Message with the
data length set to a non-zero value. Since this command does not require a data field, the
length field is set to Zero.
FF 00 07 00 00 F4 27
SOH Length OpCode Status CRC
FF 00 07 02 00 F6 27
SOH Length OpCode Status CRC
FF 00 07 00 00 F4 27
SOH Length OpCode Status CRC