MAX31855.h

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#pragma once
 
#include <cmath>
#include <cstdint>
 
#include "sys/spi.h"
 
struct MAX31855 : SPI::Device {
    MAX31855(Sink<SPI::Request> &bus, DIO cs)
        : SPI::Device(bus, cs, {SPI::Mode::M0, SPI::FirstBit::MSB}) { }
 
    double temp() {
        if (data.FAULT) return NAN;
        return data.TEMP * 0.25;
    }
 
    double internal() {
        if (data.FAULT) return NAN;
        return data.INTERNAL * 0.0625;
    }
 
    void sense() {
        bus.trypush({
            .dev = this,
            .data = 4,
            .dir = SPI::Request::MISO,
            });
    }
 
    void callback(const SPI::Request rq) override {
        int32_t raw = rq.data.buf[0]<<24 | rq.data.buf[1]<<16 | rq.data.buf[2]<<8 | rq.data.buf[3];
        data = *(sensor *)&raw;
    }
 
    struct sensor {
        uint8_t OC:1;                               
        uint8_t SCG:1;                              
        uint8_t SCV:1;                              
        uint8_t :1;
        int16_t INTERNAL:12;                       
        uint8_t FAULT:1;                            
        uint8_t :1;
        int16_t TEMP:14;                           
    } data = {};                              
};