I2C switch AC/DC mode (SIGNALlab 250-12)

Description

This 250-12 board example shows how to switch AC/DC modes over I2C using the SMBUS protocol.

Required hardware

Red Pitaya SIGNALlab 250-12

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

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.

Code - MATLAB®

%% 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');

% working with RP 250-12 v1.2. For HW revision 1.1 and newer, replace dev address with 32 (0x20)
writeline(RP,'I2C:DEV33 "/dev/i2c-0"');
writeline(RP,'I2C:FMODE ON');                           % set force mode
fprintf('Turn on AC/DC ch1 & ch2\n');

value = 0x55;
writeline(RP, append('I2C:Smbus:Write2 %d', num2str(value)));   % write 2 bytes in i2c throw SMBUS
java.lang.Thread.sleep(1000);

value = value & ~ 0x0F;
writeline(RP, append('I2C:Smbus:Write2 %d', num2str(value)));   % write 2 bytes in i2c throw SMBUS

java.lang.Thread.sleep(3000);
fprintf('Turn off AC/DC ch1 & ch2\n');

value = 0xAA;
writeline(RP, append('I2C:Smbus:Write2 %d', num2str(value)));   % write 2 bytes in i2c throw SMBUS

java.lang.Thread.sleep(1000);

value = value & ~ 0x0F;
writeline(RP, append('I2C:Smbus:Write2 %d', num2str(value)));   % write 2 bytes in i2c throw SMBUS

java.lang.Thread.sleep(1000);

value = writeread(RP,'I2C:Smbus:Read2?');       % read 2 bytes from reg 0x02 throw SMBUS
value = str2num(value(2:length(value) -1));
fprintf('Reg 0x02: %x\n', value);

%% Close connection with Red Pitaya
clear RP;

Code - Python

#!/usr/bin/env python3

import time
from struct import *
import redpitaya_scpi as scpi

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

# working on SIGNALlab 250-12 HW revision v1.2. For HW revision 1.1 and older, replace dev address with 32 (0x20)
rp.tx_txt('I2C:DEV33 "/dev/i2c-0"')
print("Init I2C")

rp.tx_txt('I2C:FMODE ON')
print("Set force mode")

#  Swich AC_DC for In 1
print("Turn on AC/DC ch1 & ch2")

value = 0x55
rp.tx_txt(f'I2C:Smbus:Write2 {value}') # write to i2c
print(f"Write value for reg 0x2: {value}")

time.sleep(1)

value = (value & ~0x0F)
rp.tx_txt(f'I2C:Smbus:Write2 {value}') # write to i2c
print(f"Write value for reg 0x2: {value}")

time.sleep(3)

print("Turn off AC/DC ch1 & ch2")

value = 0xAA
rp.tx_txt(f'I2C:Smbus:Write2 {value}') # write to i2c
print(f"Write value for reg 0x2: {value}")

time.sleep(1)

value = (value & ~0x0F)
rp.tx_txt(f'I2C:Smbus:Write2 {value}') # write to i2c
print(f"Write value for reg 0x2: {value}")

rp.tx_txt('I2C:Smbus:Read2?')
value = int(rp.rx_txt().strip('{}\n\r'))
print(f"Read value for reg 0x2: {value}")

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.

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++

/* @brief This is a simple application for testing I2C communication on a RedPitaya
*
* (c) Red Pitaya  http://www.redpitaya.com
*
* This part of code is written in C programming language.
* Please visit http://en.wikipedia.org/wiki/C_(programming_language)
* for more details on the language used herein.
*/


#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "rp_hw.h"


int main(int argc, char *argv[]){

    int res = rp_I2C_InitDevice("/dev/i2c-0",0x21); // Init i2c api.
    printf("Init result: %d\n",res);

    res = rp_I2C_setForceMode(true); // Set force mode.
    printf("Set force mode: %d\n",res);

    printf("Turn on AC/DC ch1 & ch2\n");

    uint16_t value = 0x0055;

    res = rp_I2C_SMBUS_WriteWord(0x02,value);
    printf("Write 2 bytes: %d\n",res);

    usleep(1000000);

    value = value & ~ 0x000F;

    res = rp_I2C_SMBUS_WriteWord(0x02,value);
    printf("Write 2 bytes: %d\n",res);

    usleep(3000000);

    printf("Turn off AC/DC ch1 & ch2\n");

    value = 0x00AA;

    res = rp_I2C_SMBUS_WriteWord(0x02,value);
    printf("Write 2 bytes: %d\n",res);

    usleep(1000000);

    value = value & ~ 0x000F;

    res = rp_I2C_SMBUS_WriteWord(0x02,value);
    printf("Write 2 bytes: %d\n",res);

    uint16_t read_value = 0;

    res = rp_I2C_SMBUS_ReadWord(0x02,&read_value);
    printf("Read 2 bytes: 0x%x (res: %d)\n",read_value, res);

    return 0;
}