Push button and turn on LED diode

Description

This example shows how to control Red Pitaya onboard LEDs and read the states of extension connector GPIOs. When the button is pressed, the LED will turn on.

Required hardware

• Red Pitaya device

• Push button

• Resistor 1k

• RedPitaya_Push_button

Wiring example for STEMlab 125-14 & STEMlab 125-10:

Circuit

Required software

• 2.00-23 or higher OS

Note

This code is written for 2.00-23 or higher OS. For older OS versions, please check when specific commands were released (a note is added to each command introduced in 2.00 or higher verisons).

SCPI Code Examples

Code - MATLAB®

The code is written in MATLAB. TCP client communication is used to establish socket communication with Red Pitaya, then SCPI commands are sent to configure the various Red Pitaya peripherals. Copy the code below into the MATLAB editor, save the project and press the Run button. Tested on MATLAB 2024b.

%% Define Red Pitaya as TCP/IP object
IP= 'rp-f0a235.local';                  % Input IP of your Red Pitaya...
port = 5000;
RP=tcpclient(IP, port);

%% Open connection with your Red Pitaya
RP.ByteOrder = 'big-endian';
configureTerminator(RP,'CR/LF');

writeline(RP,'DIG:RST');                % Reset digital pins and LED states
writeline(RP,'DIG:PIN:DIR IN,DIO5_N');  % Set DIO5_N  to be input
i=1;

while i<1000                            % You can set while 1 for continuous loop
    state = str2double(writeread(RP,'DIG:PIN? DIO5_N'));

    if state==0
        writeline(RP,'DIG:PIN LED5,1');
    else
        writeline(RP,'DIG:PIN LED5,0');
    end

    pause(0.1);                         % Set time delay for Red Pitaya response
    i=i+1;
end

%% Close connection with Red Pitaya
clear RP;

Code - Python

#!/usr/bin/env python3

import sys
import redpitaya_scpi as scpi

IP = 'rp-f066c8.local'
rp = scpi.scpi(IP)

# set all DIO*_N pins to inputs
for i in range(8):
    rp.tx_txt('DIG:PIN:DIR IN,DIO'+str(i)+'_N')

# copy DIOi_N pin state to LEDi state fir each i [0:7]
while 1:
    for i in range(8):
        rp.tx_txt('DIG:PIN? DIO'+str(i)+'_N')
        state = rp.rx_txt()
        rp.tx_txt('DIG:PIN LED'+str(i)+','+str(state))

rp.close()

Note

The Python functions are accessible with the latest version of the redpitaya_scpi.py document available on our GitHub. The functions represent a quality-of-life improvement as they combine the SCPI commands in an optimal order and also check for improper user inputs. The code should function at approximately the same speed without them.

For further information on functions please consult the redpitaya_scpi.py code.

Code - LabVIEW

• Download Example

API Code Examples

Note

The API code examples don’t require the use of the SCPI server. Instead, the code should be compiled and executed on the Red Pitaya itself (inside Linux OS). Instructions on how to compile the code and other useful information are here.

Code - C++ API

#include <stdio.h>
#include <stdlib.h>
#include "rp.h"

int main (int argc, char **argv) {
    rp_pinState_t state;

    // Initialization of API
    if (rp_Init() != RP_OK) {
        fprintf(stderr, "Red Pitaya API init failed!\n");
        return EXIT_FAILURE;
    }

    // configure DIO[0:7]_N to inputs
    for (int i=0; i<8; i++) {
        rp_DpinSetDirection (i+RP_DIO0_N, RP_IN);
    }

    // transfer each input state to the corresponding LED state
    while (1) {
        for (int i=0; i<8; i++) {
            rp_DpinGetState (i+RP_DIO0_N, &state);
            rp_DpinSetState (i+RP_LED0, state);
        }
    }

    // Releasing resources
    rp_Release();

    return EXIT_SUCCESS;
}

Code - Python API

#!/usr/bin/python3

import time
import rp

# Initialize the interface
rp.rp_Init()

#####! Choose one of two methods, comment the other !#####

#! METHOD 1: Interacting with Registers direclty

diox_n = [0b00000001, 0b00000010, 0b00000100, 0b00001000, 0b00010000, 0b00100000, 0b01000000, 0b10000000]
led = 0

# Set all DIO*_N pins to inputs
rp.rp_GPIOnSetDirection(0b00000000)     # 0 == input, 1 == output

# Transfer each digital input state to the corresponding LED
# Please note that Red Pitaya GPIOs default to HIGH state when left floating.
while 1:
    led = 0

    state = rp.rp_GPIOnGetState()[1]        # Get DIO_N input register

    for i in range(8):
        led += (state & diox_n[i])          # isolate each DIOx_N input and add the value to LEDs (bitwise AND)
    rp.rp_LEDSetState(led)
    time.sleep(0.2)


#! METHOD 2: Using Macros

diox_n = [rp.RP_DIO0_N, rp.RP_DIO1_N, rp.RP_DIO2_N, rp.RP_DIO3_N, rp.RP_DIO4_N, rp.RP_DIO5_N, rp.RP_DIO6_N, rp.RP_DIO7_N]
led_array = [rp.RP_LED0, rp.RP_LED1, rp.RP_LED2, rp.RP_LED3, rp.RP_LED4, rp.RP_LED5, rp.RP_LED6, rp.RP_LED7]

for i in range(8):
    rp.rp_DpinSetDirection(diox_n[i], rp.RP_IN)

while 1:
    for i in range(8):
        state = rp.rp_DpinGetState(diox_n[i])[1]        # Get state of DIOx_N
        rp.rp_DpinSetState(led_array[i], state)         # Transfer state to the corresponding LED
    time.sleep(0.2)


# Release resources
rp.rp_Release()