DNF Controls GC-32 GPIO Controller - Manual (Page 3)

Page 3 of 14
PROTOCOL DESCRIPTION
The GC-32 command consists of the following components:
Header + command + data
NOTE- The “+” is used for readability only and should not be used in the
command
The Header is hexadecimal value 0x44 0x4E 0x46
Dot notation is used in this document to describe concatenated hexadecimal values.
The header is referenced below as 44.4E.46
The command is an 8 bit value and is described below.
Data is one or more 8 bit values, and is specific to each command as described below.
All multi-byte values are formatted as big endian (MSB…LSB).
The GC-32 responds to all commands with an ACK, NAK, or the requested data. If a
complete command is not received within 2 seconds, the GC-32 will respond with a
timeout error message.
GC-32 RESPONSES
ACK= 0x04
GC-32 response: 44.4E.46.04
NAK= 0x05
GC-32 response: 44.4E.46.05.ee where ee is one of the following error codes.
0x10= Invalid command format
0x11= Invalid command
0x12= Invalid data
0x13= Command timeout error