2.3.6.1.3. Push button and turn on LED diode

2.3.6.1.3.1. 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.

2.3.6.1.3.2. Required hardware

• Red Pitaya device

• Push button

• Resistor 1k

• RedPitaya_Push_button

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

Circuit

2.3.6.1.3.3. SCPI Code Examples

2.3.6.1.3.3.1. Code - MATLAB®

The code is written in MATLAB. In the code, we use SCPI commands and TCP client communication. Copy the code from below into the MATLAB editor, save the project, and hit the “Run” button.

%% Define Red Pitaya as TCP/IP object

IP= '192.168.178.56';           % 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:PIN:DIR IN,DIO5_N');      % Set DIO5_N  to be input

i = 1;

while i < 1000                                  % You can set while 1 for a continuous loop
    state = str2num(writeread(RP,'DIG:PIN? DIO5_N'));

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

    if state==0
        writeline(RP,'DIG:PIN LED5,1');
    end
    pause(0.1)                                              % Set time delay for Red Pitaya response
    i = i+1;
end

%% Close connection with Red Pitaya
clear RP;

2.3.6.1.3.3.2. Code - Python

#!/usr/bin/env python3

import sys
import redpitaya_scpi as scpi

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

# set all DIO*_N pins to inputs
for i in range(8):
    rp_s.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_s.tx_txt('DIG:PIN? DIO'+str(i)+'_N')
        state = rp_s.rx_txt()
        rp_s.tx_txt('DIG:PIN LED'+str(i)+','+str(state))

rp_s.close()

2.3.6.1.3.3.3. Code - LabVIEW

• Download Example

2.3.6.1.3.4. 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.

2.3.6.1.3.4.1. 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;
}

2.3.6.1.3.4.2. 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()