CODEWITHSUNDEEP
c++spiraspberry-pi4wiringpiiio
Symon
Symon

Reputation: 1

Why I get Raspberry Pi MCP3008 C++ error?

I want to setup MCP3008 on Raspberry Pi 4. I took this code

#include <wiringPi.h>
#include <stdio.h>
#include <unistd.h>

int readMCP3008(int &channel);

#define CHANNELS 4
#define SPI_CHANNEL 0
#define REFERENCE_VOLTAGE 5.0

int readMCP3008(int channel) {
    if (channel < 0 || channel >= CHANNELS) {
        fprintf(stderr, "Invalid channel.\n");
        return -1;
    }

    unsigned char buffer[3];
    buffer[0] = 0b11000000 | ((channel & 0x07) << 3);
    buffer[1] = 0;
    buffer[2] = 0;

    wiringPiSPIDataRW(SPI_CHANNEL, buffer, 3);

    int result = ((buffer[0] & 0x01) << 9) | (buffer[1] << 1) | ((buffer[2] & 0x80) >> 7);
    return result;
}

int main() {
    if (wiringPiSetup() == -1) {
        fprintf(stderr, "Error initializing WiringPi.\n");
        return 1;
    }

    int spiHandle = wiringPiSPISetup(SPI_CHANNEL, 1000000); // Default SPI speed
    if (spiHandle == -1) {
        fprintf(stderr, "Error initializing SPI.\n");
        return 1;
    }

    FILE *file = fopen("mcp3008_data.txt", "w");
    if (file == NULL) {
        fprintf(stderr, "Error opening file for writing.\n");
        return 1;
    }
   
    const int numSamples = 100; // Adjust as needed
    for (int sample = 0; sample < numSamples; sample++) {
        double value0 = (readMCP3008(0) * REFERENCE_VOLTAGE / 1023.0) - 1.5;
        double value1 = (readMCP3008(1) * REFERENCE_VOLTAGE / 1023.0) - 1.5;
        double value2 = (readMCP3008(2) * REFERENCE_VOLTAGE / 1023.0) - 1.5;
        double value3 = (readMCP3008(3) * REFERENCE_VOLTAGE / 1023.0) - 1.5;

        fprintf(file, "%.2f,%.2f,%.2f,%.2f", value0, value1, value2, value3);

        fprintf(file, "\n");
 
        usleep(100000); // 100,000 microseconds = 100 milliseconds (adjust as needed)
    }
   
    fclose(file);

    return 0;
}

But it gives this error:

g++ -Wall -o "mcp3008_read" "mcp3008_read.cpp" (/home/*/Desktop dizininde)
mcp3008_read.cpp: In function ‘int readMCP3008(int)’:
mcp3008_read.cpp:27:5: error: ‘wiringPiSPIDataRW’ was not declared in this scope
   27 |     wiringPiSPIDataRW(SPI_CHANNEL, buffer, 3);
      |     ^~~~~~~~~~~~~~~~~
mcp3008_read.cpp: In function ‘int main()’:
mcp3008_read.cpp:41:21: error: ‘wiringPiSPISetup’ was not declared in this scope; did you mean ‘wiringPiSetup’?
   41 |     int spiHandle = wiringPiSPISetup(SPI_CHANNEL, 1000000); // Default SPI speed
      |                     ^~~~~~~~~~~~~~~~
      |                     wiringPiSetup

I saw couple answers from the forums, which define the functions as globals I tried but probably I tried wrong also chatgpt said I did not downloaded the wiringSPI library but I did. I check all connections and MCP3008 works on Python. I don't know how to fix this error.

Upvotes: 0

Views: 102

Answers (1)

Aincvy
Aincvy

Reputation: 549

Check header: https://github.com/WiringPi/WiringPi/blob/master/wiringPi/wiringPiSPI.h

The header file wiringPi.h didn't include wiringPiSPI.h, you need do it by yourself.

Upvotes: 0

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