MCP3xxx_Demo.cpp

Continuously read the ADC value from a channel of the MCP3xxx and print it to the terminal.

cmake_minimum_required(VERSION 3.12)
find_package(PropWare REQUIRED)
 
project(MCP3xxx_Demo)
 
create_simple_executable(${PROJECT_NAME} MCP3xxx_Demo.cpp)

 
#include <PropWare/PropWare.h>
#include <PropWare/hmi/output/printer.h>
#include <PropWare/gpio/simpleport.h>
#include <PropWare/sensor/analog/mcp3xxx.h>
 
using PropWare::MCP3xxx;
using PropWare::Port;
using PropWare::SPI;
using PropWare::SimplePort;
using PropWare::Pin;
 
static const MCP3xxx::PartNumber PART_NUMBER = MCP3xxx::PartNumber::MCP300x;
static const MCP3xxx::Channel    CHANNEL     = MCP3xxx::Channel::CHANNEL_1;
 
static const Port::Mask MOSI = Port::Mask::P0;
static const Port::Mask MISO = Port::Mask::P1;
static const Port::Mask SCLK = Port::Mask::P2;
static const Port::Mask CS   = Port::Mask::P3;
 
int main () {
    const uint16_t    DIVISOR = 1024 / 8;
    uint16_t          data = 0;
    uint32_t          loopCounter;
    uint8_t           scaledValue, i;
    uint32_t          ledOutput;
    SPI     spi(MOSI, MISO, SCLK);
    MCP3xxx adc(spi, CS, PART_NUMBER);
 
    // Set the Quickstart LEDs for output (used as a secondary display)
    SimplePort scale(Port::P16, 8, Pin::Dir::OUT);
 
    // Though this functional call is not necessary (default value is 0), I
    // want to bring attention to this function. It will determine whether the
    // adc.read* functions will always explicitly set the SPI modes before
    // each call, or assume that the SPI cog is still running in the proper
    // configuration
    adc.always_set_spi_mode(0);
 
    pwOut << "Welcome to the MCP3xxx demo!\n";
 
    while (1) {
        loopCounter = SECOND / 2 + CNT;
 
        // Loop over the LED output very quickly, until we are within 1
        // millisecond of total period
        while (abs(loopCounter - CNT) > MILLISECOND) {
            data = adc.read(CHANNEL);
 
            // Turn on LEDs proportional to the analog value
            scaledValue = (uint8_t) ((data + DIVISOR / 2 - 1) / DIVISOR);
            ledOutput   = 0;
            for (i      = 0; i < scaledValue; ++i)
                ledOutput = (ledOutput << 1) | 1;
            scale.write(ledOutput);
        }
 
        pwOut.printf("Channel %d is reading: %d\n", static_cast<int>(CHANNEL), data);
    }
}