Lantronix XPort manual Guidelines, Commands, Byte 0 Command Types

5: GPIO Interface

Guidelines

The GPIO control protocol is described from the PC side. Send means from PC to XPort. Response comes from XPort to PC.

The protocol allows for control of up to 32 GPIOs. How many are actually available depends on the product. XPort has only three.

The parameters are four bytes long and represent GPIOs 0-31, with GPIO0 in bit 0 of the first byte (Little Endian). Parameter bits for configurable pins not configured as GPIOs are undefined for Get commands and ignored on Set commands.

Every command consists of nine bytes: one command type of one byte and two parameters of four bytes each.

Command		Parameter 1				Parameter 2
0	1	2	3	4	5	6	7	8

On some commands, one or all parameters are ignored.

For UDP, command type and parameters need to be in the same datagram.

Responses to valid commands are always five bytes long, consisting of the returned command byte and as parameters in the current or updated values. In case of an invalid command, only one byte with value 0FFh is returned.

Command		Parameter 1
0	1	2	3	4

When sending a command (TCP and UDP), wait for the response before sending the next command.

Commands

Byte 0 Command Types

10h	Get functions
11h	Get directions (input or output)
12h	Get active levels (high active or low active)
13h	Get current states (active or not active)
19h	Set directions
1Ah	Set active levels
1Bh	Set current states

There is no Set functions command. Since the pin’s function depends on the hardware in which the XPort is embedded, that configuration is only allowed via 77FE. Settings changed by any of the Set commands are not stored and are lost when the unit is powered down or rebooted.

XPort™ User Guide 46