Digital IO Server

Digital IO Server is a simple SCPI server for Arduino Uno based devices that allows to control digital input and output pins over Ethernet. It uses the Vrekrer SCPI parser library to parse SCPI commands.

It is designed to be used with the Keyestudio 5500 board or Arduino Uno with Ethernet shield.

Features

• control and query of digital inputs and outputs via Ethernet
• Configuration of networks settings (IP, gateway, subnet, port) via SCPI command
• Error handling and return via SCPI
• Non-volatile storage of network settings in EEPROM
• GPIO reset and device reboot via SCPI command

Hardware

• Arduino Uno with Ethernet Shield (W5100/W5200/W5500)
• Keyestudio 5500 board

Pin assignment

Digital inputs:
DIn0 = Pin 14
DIn1 = Pin 15
DIn2 = Pin 16
DIn3 = Pin 17
DIn4 = Pin 18
DIn5 = Pin 19

Digital outputs:
DOut0 = Pin 0
DOut1 = Pin 1
DOut2 = Pin 2
DOut3 = Pin 3
DOut4 = Pin 4
DOut5 = Pin 5
DOut6 = Pin 6
DOut7 = Pin 7

SCPI commands

Command	Description
*IDN?	Query device identification string
*RST	Resets and initializes all digital IOs
SYSTem:ERRor?	Queries and returns last device error
SYSTem:REBoot	Reboots the device
SYSTem:LAN:CONFig?	Queries and return actual netwirk configuration
SYSTem:LAN:CONFig	Set network configuration (IP, gateway, subnet, port)
DigitalIn#?	Queries and returns status of digital input pin
DigitalOut#	Set digital output pin
DigitalOut#?	Queries and returns status of digital output pin

Examples:

• DigitalIn0? – Request status from digital input 0, pin 14
• DigitalOut3 HIGH – Set digital output DOut3 to HIGH, pin 3
• SYSTem:LAN:CONFig 192.168.1.100,192.168.1.1,255.255.255.0,5025 – Set network configuration

DigitalIn<index>?
  Queries the logic state of DigitalIn[index] pin
  Return values are "HIGH" or "LOW"
  Examples:
  DigitalIn0?     (Queries the state of digital input 0 pin)
  DigitalIn5?     (Queries the state of digital input 5 pin)

DigitalOut<index>?
  Queries the logic state of DigitalOut[index] pin
  Return values are "HIGH" or "LOW"
  Examples:
  DigitalOut4?    (Queries the state of digital output 4 pin)
  DigitalOut6?    (This does nothing as digital output 6 does not exists)

DigitalOut<index> state
  Sets the logic state of DigitalOut[index] pin
  Valid states are : "HIGH", "LOW", "ON", "OFF", "1" and "0"
  and any lowercase/uppercase combinations
  Examples:
  DigitalOut4 HIGH  (Sets digital output 4 pin to HIGH)
  DigitalOut2 Off   (Sets digital output 2 pin to LOW)
  DigitalOut0 1     (Sets digital output 0 pin to HIGH)

Error codes

• 0: SCPI_Parser::ErrorCode::NoError
• 1: SCPI_Parser::ErrorCode::UnknownCommand
• 2: SCPI_Parser::ErrorCode::Timeout
• 3: SCPI_Parser::ErrorCode::BufferOverflow
• 4: SCPI_Parser::ErrorCode::InvalidParameter

Linux usage

The digital IO server can be controlled under Linux using netcat (nc).

Example:

~$ echo "SYST:LAN:CONF?" | nc 192.168.178.232 5025
192.168.178.232,192.168.178.1,255.255.255.0,5025

~$ echo "DigitalOut0?" | nc 192.168.178.232 5025
HIGH