IoExpanderSPI.hpp

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#pragma once
 
#include "../SensorBuildOpt.h"
#if !SENSORLIB_EXCLUDE_IO_EXPANDER_SPI
 
#include "IoExpanderBase.hpp"
 
class IoExpanderSPI
{
public:
    IoExpanderSPI(): _mosi(-1),  _sck(-1), _miso(-1), _order(0), _cs(-1) {}
 
    ~IoExpanderSPI() = default;
 
    bool beginSPI(IoExpanderBase &base, int mosi, int miso, int sck, int cs)
    {
        _base = &base;
        _mosi = mosi;
        _miso = miso;
        _sck = sck;
        _cs = cs;
 
        if (_mosi == -1 || sck == -1) {
            SENSORLIB_LOG_E("MOSI and SCK pins must be specified");
            return false;
        }
 
        _base->pinMode(_mosi, OUTPUT);
        _base->pinMode(_sck, OUTPUT);
 
        if (_cs != -1) {
            _base->pinMode(_cs, OUTPUT);
            _base->digitalWrite(_cs, HIGH);
        }
 
        if (_miso != -1) {
            _base->pinMode(_miso, INPUT);
        }
        _base->digitalWrite(_mosi, HIGH);
        _base->digitalWrite(_sck, HIGH);
        return true;
    }
 
    void setBitOrder(uint8_t order)
    {
        _order = order & 1;
    }
 
    uint8_t transfer8(uint8_t val)
    {
        return transferDataBits(val, 8);
    }
 
    uint16_t transfer9(uint16_t val)
    {
        return transferDataBits(val, 9);
    }
 
    uint32_t transferDataBits(uint32_t val, uint32_t bits)
    {
        if (!_base) {
            SENSORLIB_LOG_E("SPI not initialized (call beginSPI first)");
            return 0;
        }
        uint32_t out = 0;
        if (_cs != -1) _base->digitalWrite(_cs, LOW);
        for (uint32_t i = 0; i < bits; i++) {
            _base->digitalWrite(_sck, LOW);
            out <<= 1;
            if (_miso != -1 && _base->digitalRead(_miso)) out |= 0x01;
            bool bitVal;
            if (_order == 0) // MSB first
                bitVal = (val >> (bits - 1 - i)) & 1;
            else             // LSB first
                bitVal = (val >> i) & 1;
            _base->digitalWrite(_mosi, bitVal ? HIGH : LOW);
            _base->digitalWrite(_sck, HIGH);
        }
        if (_cs != -1) _base->digitalWrite(_cs, HIGH);
        return out;
    }
 
private:
    int _mosi;          
    int _sck;           
    int _miso;          
    int _order;         
    int _cs;            
    IoExpanderBase *_base;  
};
 
#endif