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公開済みのRP1-GPIOライブラリを利用したソフトウェアSPIライブラリを作ってみた。

【仕様】
・マスターモードのみ
・※最大通信速度はwrite()のみ5MHz、read()/transfer()は500KHz程度まで。
・データビット数は、1-32ビットに対応
・ビットオーダー対応
・チップセレクト対応(ポラリティ付き)
・ArduinoのSPI準拠クラス対応

※ソフトウェアのみでこれ以上の高速化は無理！。より高速な通信速度が必要ならRP1チップのSPI或いはPIOを使うしかない。

begin()にて、主要な動作を指定する。

void begin(MODE mode, long speed, int databit = 8, BITORDER bitorder = MSBFIRST, long cs_delay);

databit <= 8
write/read/writeAndRead/transferメソッドのbufには1バイト型配列アドレスを指定し、lenにその配列数を指定する。

databit <= 16
write/read/writeAndRead/transferメソッドのbufには2バイト型配列アドレスを指定し、lenにその配列数を指定する。

databit <= 32
write/read/writeAndRead/transferメソッドのbufには4バイト型配列アドレスを指定し、lenにその配列数を指定する。

【使い方のサンプル】

#include <stdio.h>
#include "rp1-gpio.h"
#include "spi-gpio.h"

RP1_GPIO rp1;

/* with chip-select
   ピン番号を正数指定したときは、Select=LOW, Deselect=HIGH
   ピン番号を負数指定したときは、Select=HIGH, Deselect=LOW
   ※ピン番号0は負数指定できないので注意！
*/
SPI_GPIO spi(rp1, 11, 10, 9, { 8, -7 });

/* without chip-select */
SPI_GPIO spi(rp1, 11, 10, 9);

int main(int argc, char **argv)
{
  char wbuf[16], rbuf[16];
  rp1.begin();
  spi.begin(spi.MODE3, 1000000); /* MODE3, 1MHz, 8bit, MSBFIRST, CS_DELAY:1000ns */

  /* simple call (with chip-select) */
  spi.write(0, wbuf, sizeof(wbuf));
  spi.read(0, rbuf, sizeof(rbuf));
  spi.writeAndRead(0, wbuf, sizeof(wbuf), rbuf, sizeof(rbuf));
  spi.transfer(0, wbuf, sizeof(wbuf));

  /* multiple call (with chip-select) */
  spi.select(0);
    spi.write(wbuf, sizeof(wbuf));
    spi.read(rbuf, sizeof(rbuf));
    spi.writeAndRead(wbuf, sizeof(wbuf), rbuf, sizeof(rbuf));
    spi.transfer(wbuf, sizeof(wbuf));
  spi.deselect(0);

  /* multiple call (without chip-select) */
  rp1.pinMode(CS[0], rp1.OUTPUT);
  rp1.digitalWrite(CS[0], rp1.LOW);
  spi.select();
    spi.write(wbuf, sizeof(wbuf));
    spi.read(rbuf, sizeof(rbuf));
    spi.writeAndRead(wbuf, sizeof(wbuf), rbuf, sizeof(rbuf));
    spi.transfer(wbuf, sizeof(wbuf));
  spi.deselect();
  rp1.digitalWrite(CS[0], rp1.HIGH);

  rp1.end();
  return 0;
}

#include <stdio.h>

#include "rp1-gpio.h"

#include "spi-gpio.h"

RP1_GPIO rp1;

/* with chip-select

ピン番号を正数指定したときは、Select=LOW, Deselect=HIGH

ピン番号を負数指定したときは、Select=HIGH, Deselect=LOW

※ピン番号0は負数指定できないので注意！

SPI_GPIO spi(rp1, 11, 10, 9, { 8, -7 });

/* without chip-select */

SPI_GPIO spi(rp1, 11, 10, 9);

int main(int argc, char **argv)

{

char wbuf[16], rbuf[16];

rp1.begin();

spi.begin(spi.MODE3, 1000000); /* MODE3, 1MHz, 8bit, MSBFIRST, CS_DELAY:1000ns */

/* simple call (with chip-select) */

spi.write(0, wbuf, sizeof(wbuf));

spi.read(0, rbuf, sizeof(rbuf));

spi.writeAndRead(0, wbuf, sizeof(wbuf), rbuf, sizeof(rbuf));

spi.transfer(0, wbuf, sizeof(wbuf));

/* multiple call (with chip-select) */

spi.select(0);

spi.write(wbuf, sizeof(wbuf));

spi.read(rbuf, sizeof(rbuf));

spi.writeAndRead(wbuf, sizeof(wbuf), rbuf, sizeof(rbuf));

spi.transfer(wbuf, sizeof(wbuf));

spi.deselect(0);

/* multiple call (without chip-select) */

rp1.pinMode(CS[0], rp1.OUTPUT);

rp1.digitalWrite(CS[0], rp1.LOW);

spi.select();

spi.write(wbuf, sizeof(wbuf));

spi.read(rbuf, sizeof(rbuf));

spi.writeAndRead(wbuf, sizeof(wbuf), rbuf, sizeof(rbuf));

spi.transfer(wbuf, sizeof(wbuf));

spi.deselect();

rp1.digitalWrite(CS[0], rp1.HIGH);

rp1.end();

return 0;

}

【修正】
2025-06-24
バグ修正とおまじない(ＨＷ誤動作防止)の追加。

2025-06-23
非セレクト時のエラー処理を追加したのとコンストラクタでチップセレクトピンの配列を指定できるようにしてみた。

SPI_GPIO SPI(GPIO, 11, 10, 9, { 8, 7 });

SPI_GPIO(RP1_GPIO &gpio, int sclk, int mosi, int miso, std::initializer_list<int> cslist)
SPIClass(RP1_GPIO &gpio, int sclk, int mosi, int miso, std::initializer_list<int> cslist)

1 2	SPI_GPIO(RP1_GPIO &gpio, int sclk, int mosi, int miso, std::initializer_list<int> cslist) SPIClass(RP1_GPIO &gpio, int sclk, int mosi, int miso, std::initializer_list<int> cslist)

2025-06-21
slave()の追加とチップセレクト・ピンを直接指定できる可変長引数のコンストラクターを追加。

2025-06-05
制御タイミングの最適化。

2025-06-04
MODE1/2の制御タイミングを変更。

2025-05-13
ソースをより読みやすくしてみた。

2025-05-08
関数の追加とArduino準拠クラスの追加。
uint32_t transfer(uint32_t data)
class SPISettings
class SPIClass

2025-05-06
rp1-gpio.hのpinMode()修正にともなう初期化処理の変更。

【ライブラリ】

/*
  spi-gpio.h - Software SPI Driver for RP1-GPIO

  Copyright (c) 2025 Sasapea's Lab. All right reserved.

  This program is free software: you can redistribute it and/or
  modify it under the terms of the GNU General Public License as
  published by the Free Software Foundation, either version 3 of
  the License, or at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  See the GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#pragma once

#include <stdlib.h>
#include <stdarg.h>
#include <vector>
#include <initializer_list>
#include "rp1-gpio.h"

class SPI_GPIO
{
  public:

    static constexpr int ERROR = -1;

    typedef enum
    {
      MODE0,
      MODE1,
      MODE2,
      MODE3,
    } MODE;

    typedef enum
    {
      LSBFIRST,
      MSBFIRST,
    } BITORDER;

    SPI_GPIO(RP1_GPIO &gpio, int sclk, int mosi, int miso, const int *cspins = nullptr, size_t count = 0)
      : _gpio(&gpio), _sclk(sclk), _mosi(mosi), _miso(miso), _selected(false), _slave(-1)
    {
      setupCS(cspins, count);
    }

    SPI_GPIO(RP1_GPIO &gpio, int sclk, int mosi, int miso, size_t count, ...)
      : SPI_GPIO(gpio, sclk, mosi, miso)
    {
      va_list ap;
      va_start(ap, count);
      setupCS(ap, count);
      va_end(ap);
    }

    SPI_GPIO(RP1_GPIO &gpio, int sclk, int mosi, int miso, std::initializer_list<int> cslist)
    : SPI_GPIO(gpio, sclk, mosi, miso)
    {
      setupCS(cslist);
    }

    virtual ~SPI_GPIO(void)
    {
    }

    void begin(MODE mode, long speed, int databit = 8, BITORDER bitorder = MSBFIRST, long delay = 1000)
    {
      _mode  = mode;
      _clock = 1000000000UL / 2 / speed;
      _dbit  = databit > 0 ? databit - 1 : 0;
      _dmsb  = 1 << _dbit;
      _bord  = bitorder;
      _delay = delay;
      initIO();
    }

    int write(int cs, const void *buf, size_t len)
    {
      int rv;
      if ((rv = select(cs)) == 0)
      {
        rv = write0(buf, len);
        deselect(cs);
      }
      return rv;
    }

    int read(int cs, void *buf, size_t len)
    {
      int rv;
      if ((rv = select(cs)) == 0)
      {
        rv = read0(buf, len);
        deselect(cs);
      }
      return rv;
    }

    int writeAndRead(int cs, const void *wbuf, size_t wlen, void *rbuf, size_t rlen)
    {
      int rv;
      if ((rv = select(cs)) == 0)
      {
        rv = writeAndRead0(wbuf, wlen, rbuf, rlen);
        deselect(cs);
      }
      return rv;
    }

    int transfer(int cs, void *buf, size_t len)
    {
      int rv;
      if ((rv = select(cs)) == 0)
      {
        rv = transfer0(buf, len);
        deselect(cs);
      }
      return rv;
    }

    uint32_t transfer(int cs, uint32_t data)
    {
      uint32_t rv;
      if ((rv = select(cs)) == 0)
      {
        data = transfer0(data);
        deselect(cs);
      }
      return rv;
    }

    bool select(int cs = -1)
    {
      return select0(cs, true);
    }

    bool deselect(int cs = -1)
    {
      return select0(cs, false);
    }

    void slave(int cs = -1)
    {
      _slave = cs;
    }

    int write(const void *buf, size_t len)
    {
      return _slave < 0 ? write0(buf, len) : write(_slave, buf, len);
    }

    int read(void *buf, size_t len)
    {
      return _slave < 0 ? read0(buf, len) : read(_slave, buf, len);
    }

    int writeAndRead(const void *wbuf, size_t wlen, void *rbuf, size_t rlen)
    {
      return _slave < 0 ? writeAndRead0(wbuf, wlen, rbuf, rlen) : writeAndRead(_slave, wbuf, wlen, rbuf, rlen);
    }

    void transfer(void *buf, size_t len)
    {
      if (_slave < 0)
        transfer0(buf, len);
      else
        transfer(_slave, buf, len);
    }

    uint32_t transfer(uint32_t data)
    {
      return _slave < 0 ? transfer0(data) : transfer(_slave, data);
    }

  protected:

    void setupCS(const int *pins, size_t size)
    {
      _cslist.clear();
      if (pins)
      {
        for (size_t i = 0; i < size; ++i)
          _cslist.push_back(pins[i]);
      }
    }

    void setupCS(va_list ap, size_t size)
    {
      _cslist.clear();
      for (size_t i = 0; i < size; ++i)
        _cslist.push_back(va_arg(ap, int));
    }

    void setupCS(std::initializer_list<int>& list)
    {
      _cslist = list;
    }

  private:

    static constexpr int CPHA = 1;
    static constexpr int CPOL = 2;

    static constexpr int LOW  = 0;
    static constexpr int HIGH = 1;

    static constexpr long DELAY_AD = 120L; /* 120ns */

    RP1_GPIO *_gpio;
    int       _sclk;
    int       _mosi;
    int       _miso;
    bool      _selected;
    int       _slave;
    std::vector<int> _cslist;
    MODE      _mode;
    long      _clock;
    int       _dbit;
    uint32_t  _dmsb;
    BITORDER  _bord;
    long      _delay;

    inline void output(int pin, int data)
    {
      _gpio->digitalWrite(pin, data ? _gpio->HIGH : _gpio->LOW);
    }

    inline int input(int pin)
    {
      return _gpio->digitalRead(pin) ? HIGH : LOW;
    }

    void outputCS(int pin, bool enable)
    {
      int value;
      if (pin >= 0)
        value = enable ? LOW : HIGH;
      else
        value = enable ? HIGH : LOW;
      output(abs(pin), value);
    }

    void initIO(void)
    {
      _gpio->pinMode(_sclk, _gpio->OUTPUT, _mode & CPOL ? _gpio->HIGH : _gpio->LOW);
      _gpio->pinMode(_mosi, _gpio->OUTPUT);
      _gpio->pinMode(_miso, _gpio->INPUT);
      for (size_t i = 0; i < _cslist.size(); ++i)
      {
        int cs = _cslist[i];
        _gpio->pinMode(abs(cs), _gpio->OUTPUT, cs >= 0 ? _gpio->HIGH : _gpio->LOW);
      }
    }

    inline void data(int data)
    {
      output(_mosi, data);
    }

    inline void clock(int data)
    {
      output(_sclk, data);
    }

    inline void delay(long ns)
    {
      if ((ns -= DELAY_AD) > 0)
        _gpio->delayNanoseconds(ns);
    }

    int select0(int cs, bool enable)
    {
      if (!enable)
      {
        delay(_clock);
        clock(_mode & CPOL ? HIGH : LOW);
        delay(_delay);
      }
      if (cs >= 0)
      {
        if ((size_t)cs >= _cslist.size())
          return ERROR;
        outputCS(_cslist[cs], enable);
      }
      if (enable)
      {
        delay(_delay);
        clock(LOW);
      }
      _selected = enable;
      return 0;
    }

    uint32_t xfer(uint32_t b, bool read = true)
    {
      input(_miso); /* good-luck charm */
      if ((_mode == MODE0) || (_mode == MODE3))
      {
        for (int i = 0; i <= _dbit; ++i)
        {
          data(b & (_bord ? _dmsb : 1));
          delay(_clock);
          clock(HIGH);
          if (_bord)
            b = (b << 1) | (read ? input(_miso) : 0);
          else
            b = (b >> 1) | (read ? input(_miso) << _dbit : 0);
          delay(_clock);
          clock(LOW);
        }
      }
      else
      {
        for (int i = 0; i <= _dbit; ++i)
        {
          delay(_clock);
          clock(HIGH);
          data(b & (_bord ? _dmsb : 1));
          delay(_clock);
          clock(LOW);
          if (_bord)
            b = (b << 1) | (read ? input(_miso) : 0);
          else
            b = (b >> 1) | (read ? input(_miso) << _dbit : 0);
        }
      }
      return b & (_dmsb | (_dmsb - 1));
    }

    int write0(const void *buf, size_t len)
    {
      if (!_selected || (_dbit >= 32))
        return ERROR;
      if (_dbit < 8)
      {
        const uint8_t *p = (const uint8_t *)buf;
        for (size_t i = 0; i < len; ++i)
          xfer(p[i], false);
      }
      else if (_dbit < 16)
      {
        const uint16_t *p = (const uint16_t *)buf;
        for (size_t i = 0; i < len; ++i)
          xfer(p[i], false);
      }
      else
      {
        const uint32_t *p = (const uint32_t *)buf;
        for (size_t i = 0; i < len; ++i)
          xfer(p[i], false);
      }
      return len;
    }

    int read0(void *buf, size_t len)
    {
      if (!_selected || (_dbit >= 32))
        return ERROR;
      if (_dbit < 8)
      {
        uint8_t *p = (uint8_t *)buf;
        for (size_t i = 0; i < len; ++i)
          p[i] = xfer(0xFFFFFFFF);
      }
      else if (_dbit < 16)
      {
        uint16_t *p = (uint16_t *)buf;
        for (size_t i = 0; i < len; ++i)
          p[i] = xfer(0xFFFFFFFF);
      }
      else
      {
        uint32_t *p = (uint32_t *)buf;
        for (size_t i = 0; i < len; ++i)
          p[i] = xfer(0xFFFFFFFF);
      }
      return len;
    }

    int writeAndRead0(const void *wbuf, size_t wlen, void *rbuf, size_t rlen)
    {
      if (wbuf && wlen)
      {
        int rv = write0(wbuf, wlen);
        if ((size_t)rv != wlen)
          return rv < 0 ? rv : 0;
      }
      return rbuf && rlen ? read0(rbuf, rlen) : 0;
    }

    int transfer0(void *buf, size_t len)
    {
      if (!_selected || (_dbit >= 32))
        return ERROR;
      if (_dbit < 8)
      {
        uint8_t *p = (uint8_t *)buf;
        for (size_t i = 0; i < len; ++i)
          p[i] = xfer(p[i]);
      }
      else if (_dbit < 16)
      {
        uint16_t *p = (uint16_t *)buf;
        for (size_t i = 0; i < len; ++i)
          p[i] = xfer(p[i]);
      }
      else
      {
        uint32_t *p = (uint32_t *)buf;
        for (size_t i = 0; i < len; ++i)
          p[i] = xfer(p[i]);
      }
      return len;
    }

    uint32_t transfer0(uint32_t data)
    {
      return !_selected || (_dbit >= 32) ? (uint32_t)ERROR : xfer(data);
    }
};

class SPISettings
{
  public:

    SPISettings(void) : SPISettings(4000000, SPI_GPIO::MSBFIRST, SPI_GPIO::MODE0)
    {
    }

    SPISettings(long speed, SPI_GPIO::BITORDER bitOrder, SPI_GPIO::MODE dataMode, int dataBit = 8, long delay = 1000)
      : _speed(speed), _bitOrder(bitOrder), _dataMode(dataMode), _dataBit(dataBit), _delay(delay)
    {
    }

    virtual ~SPISettings(void)
    {
    }

  private:

    long               _speed;
    SPI_GPIO::BITORDER _bitOrder;
    SPI_GPIO::MODE     _dataMode;
    int                _dataBit;
    long               _delay;

    friend class SPIClass;
};


class SPIClass : public SPI_GPIO
{
  public:

    SPIClass(RP1_GPIO &gpio, int sclk, int mosi, int miso, const int *cspins = nullptr, size_t count = 0)
      : SPI_GPIO(gpio, sclk, mosi, miso, cspins, count)
    {
    }

    SPIClass(RP1_GPIO &gpio, int sclk, int mosi, int miso, size_t count, ...)
      : SPIClass(gpio, sclk, mosi, miso)
    {
      va_list ap;
      va_start(ap, count);
      setupCS(ap, count);
      va_end(ap);
    }

    SPIClass(RP1_GPIO &gpio, int sclk, int mosi, int miso, std::initializer_list<int> cslist)
      : SPIClass(gpio, sclk, mosi, miso)
    {
      setupCS(cslist);
    }

    virtual ~SPIClass(void)
    {
    }

    void begin(void)
    {
    }

    void end(void)
    {
    }

    inline void beginTransaction(SPISettings &settings)
    {
      SPI_GPIO::begin(settings._dataMode, settings._speed, settings._dataBit, settings._bitOrder, settings._delay);
    }

    inline void endTransaction(void)
    {
    }

    inline uint32_t transfer(uint32_t data)
    {
      return SPI_GPIO::transfer(data);
    }

    inline void transfer(void *buf, size_t count)
    {
      SPI_GPIO::transfer(buf, count);
    }
};

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spi-gpio.h - Software SPI Driver for RP1-GPIO

This program is free software: you can redistribute it and/or

modify it under the terms of the GNU General Public License as

published by the Free Software Foundation, either version 3 of

the License, or at your option) any later version.

This program is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program. If not, see <https://www.gnu.org/licenses/>.

#pragma once

#include <stdlib.h>

#include <stdarg.h>

#include <vector>

#include <initializer_list>

#include "rp1-gpio.h"

class SPI_GPIO

{

public:

static constexpr int ERROR = -1;

typedef enum

{

MODE0,

MODE1,

MODE2,

MODE3,

} MODE;

typedef enum

{

LSBFIRST,

MSBFIRST,

} BITORDER;

SPI_GPIO(RP1_GPIO &gpio, int sclk, int mosi, int miso, const int *cspins = nullptr, size_t count = 0)

: _gpio(&gpio), _sclk(sclk), _mosi(mosi), _miso(miso), _selected(false), _slave(-1)

{

setupCS(cspins, count);

}

SPI_GPIO(RP1_GPIO &gpio, int sclk, int mosi, int miso, size_t count, ...)

: SPI_GPIO(gpio, sclk, mosi, miso)

{

va_list ap;

va_start(ap, count);

setupCS(ap, count);

va_end(ap);

}

SPI_GPIO(RP1_GPIO &gpio, int sclk, int mosi, int miso, std::initializer_list<int> cslist)

: SPI_GPIO(gpio, sclk, mosi, miso)

{

setupCS(cslist);

}

virtual ~SPI_GPIO(void)

{

}

void begin(MODE mode, long speed, int databit = 8, BITORDER bitorder = MSBFIRST, long delay = 1000)

{

_mode = mode;

_clock = 1000000000UL / 2 / speed;

_dbit = databit > 0 ? databit - 1 : 0;

_dmsb = 1 << _dbit;

_bord = bitorder;

_delay = delay;

initIO();

}

int write(int cs, const void *buf, size_t len)

{

int rv;

if ((rv = select(cs)) == 0)

{

rv = write0(buf, len);

deselect(cs);

}

return rv;

}

int read(int cs, void *buf, size_t len)

{

int rv;

if ((rv = select(cs)) == 0)

{

rv = read0(buf, len);

deselect(cs);

}

return rv;

}

int writeAndRead(int cs, const void *wbuf, size_t wlen, void *rbuf, size_t rlen)

{

int rv;

if ((rv = select(cs)) == 0)

{

rv = writeAndRead0(wbuf, wlen, rbuf, rlen);

deselect(cs);

}

return rv;

}

int transfer(int cs, void *buf, size_t len)

{

int rv;

if ((rv = select(cs)) == 0)

{

rv = transfer0(buf, len);

deselect(cs);

}

return rv;

}

uint32_t transfer(int cs, uint32_t data)

{

uint32_t rv;

if ((rv = select(cs)) == 0)

{

data = transfer0(data);

deselect(cs);

}

return rv;

}

bool select(int cs = -1)

{

return select0(cs, true);

}

bool deselect(int cs = -1)

{

return select0(cs, false);

}

void slave(int cs = -1)

{

_slave = cs;

}

int write(const void *buf, size_t len)

{

return _slave < 0 ? write0(buf, len) : write(_slave, buf, len);

}

int read(void *buf, size_t len)

{

return _slave < 0 ? read0(buf, len) : read(_slave, buf, len);

}

int writeAndRead(const void *wbuf, size_t wlen, void *rbuf, size_t rlen)

{

return _slave < 0 ? writeAndRead0(wbuf, wlen, rbuf, rlen) : writeAndRead(_slave, wbuf, wlen, rbuf, rlen);

}

void transfer(void *buf, size_t len)

{

if (_slave < 0)

transfer0(buf, len);

else

transfer(_slave, buf, len);

}

uint32_t transfer(uint32_t data)

{

return _slave < 0 ? transfer0(data) : transfer(_slave, data);

}

protected:

void setupCS(const int *pins, size_t size)

{

_cslist.clear();

if (pins)

{

for (size_t i = 0; i < size; ++i)

_cslist.push_back(pins[i]);

}

void setupCS(va_list ap, size_t size)

{

_cslist.clear();

for (size_t i = 0; i < size; ++i)

_cslist.push_back(va_arg(ap, int));

}

void setupCS(std::initializer_list<int>& list)

{

_cslist = list;

}

private:

static constexpr int CPHA = 1;

static constexpr int CPOL = 2;

static constexpr int LOW = 0;

static constexpr int HIGH = 1;

static constexpr long DELAY_AD = 120L; /* 120ns */

RP1_GPIO *_gpio;

int _sclk;

int _mosi;

int _miso;

bool _selected;

int _slave;

std::vector<int> _cslist;

MODE _mode;

long _clock;

int _dbit;

uint32_t _dmsb;

BITORDER _bord;

long _delay;

inline void output(int pin, int data)

{

_gpio->digitalWrite(pin, data ? _gpio->HIGH : _gpio->LOW);

}

inline int input(int pin)

{

return _gpio->digitalRead(pin) ? HIGH : LOW;

}

void outputCS(int pin, bool enable)

{

int value;

if (pin >= 0)

value = enable ? LOW : HIGH;

else

value = enable ? HIGH : LOW;

output(abs(pin), value);

}

void initIO(void)

{

_gpio->pinMode(_sclk, _gpio->OUTPUT, _mode & CPOL ? _gpio->HIGH : _gpio->LOW);

_gpio->pinMode(_mosi, _gpio->OUTPUT);

_gpio->pinMode(_miso, _gpio->INPUT);

for (size_t i = 0; i < _cslist.size(); ++i)

{

int cs = _cslist[i];

_gpio->pinMode(abs(cs), _gpio->OUTPUT, cs >= 0 ? _gpio->HIGH : _gpio->LOW);

}

inline void data(int data)

{

output(_mosi, data);

}

inline void clock(int data)

{

output(_sclk, data);

}

inline void delay(long ns)

{

if ((ns -= DELAY_AD) > 0)

_gpio->delayNanoseconds(ns);

}

int select0(int cs, bool enable)

{

if (!enable)

{

delay(_clock);

clock(_mode & CPOL ? HIGH : LOW);

delay(_delay);

}

if (cs >= 0)

{

if ((size_t)cs >= _cslist.size())

return ERROR;

outputCS(_cslist[cs], enable);

}

if (enable)

{

delay(_delay);

clock(LOW);

}

_selected = enable;

return 0;

}

uint32_t xfer(uint32_t b, bool read = true)

{

input(_miso); /* good-luck charm */

if ((_mode == MODE0) || (_mode == MODE3))

{

for (int i = 0; i <= _dbit; ++i)

{

data(b & (_bord ? _dmsb : 1));

delay(_clock);

clock(HIGH);

if (_bord)

b = (b << 1) | (read ? input(_miso) : 0);

else

b = (b >> 1) | (read ? input(_miso) << _dbit : 0);

delay(_clock);

clock(LOW);

}

else

{

for (int i = 0; i <= _dbit; ++i)

{

delay(_clock);

clock(HIGH);

data(b & (_bord ? _dmsb : 1));

delay(_clock);

clock(LOW);

if (_bord)

b = (b << 1) | (read ? input(_miso) : 0);

else

b = (b >> 1) | (read ? input(_miso) << _dbit : 0);

}

return b & (_dmsb | (_dmsb - 1));

}

int write0(const void *buf, size_t len)

{

if (!_selected || (_dbit >= 32))

return ERROR;

if (_dbit < 8)

{

const uint8_t *p = (const uint8_t *)buf;

for (size_t i = 0; i < len; ++i)

xfer(p[i], false);

}

else if (_dbit < 16)

{

const uint16_t *p = (const uint16_t *)buf;

for (size_t i = 0; i < len; ++i)

xfer(p[i], false);

}

else

{

const uint32_t *p = (const uint32_t *)buf;

for (size_t i = 0; i < len; ++i)

xfer(p[i], false);

}

return len;

}

int read0(void *buf, size_t len)

{

if (!_selected || (_dbit >= 32))

return ERROR;

if (_dbit < 8)

{

uint8_t *p = (uint8_t *)buf;

for (size_t i = 0; i < len; ++i)

p[i] = xfer(0xFFFFFFFF);

}

else if (_dbit < 16)

{

uint16_t *p = (uint16_t *)buf;

for (size_t i = 0; i < len; ++i)

p[i] = xfer(0xFFFFFFFF);

}

else

{

uint32_t *p = (uint32_t *)buf;

for (size_t i = 0; i < len; ++i)

p[i] = xfer(0xFFFFFFFF);

}

return len;

}

int writeAndRead0(const void *wbuf, size_t wlen, void *rbuf, size_t rlen)

{

if (wbuf && wlen)

{

int rv = write0(wbuf, wlen);

if ((size_t)rv != wlen)

return rv < 0 ? rv : 0;

}

return rbuf && rlen ? read0(rbuf, rlen) : 0;

}

int transfer0(void *buf, size_t len)

{

if (!_selected || (_dbit >= 32))

return ERROR;

if (_dbit < 8)

{

uint8_t *p = (uint8_t *)buf;

for (size_t i = 0; i < len; ++i)

p[i] = xfer(p[i]);

}

else if (_dbit < 16)

{

uint16_t *p = (uint16_t *)buf;

for (size_t i = 0; i < len; ++i)

p[i] = xfer(p[i]);

}

else

{

uint32_t *p = (uint32_t *)buf;

for (size_t i = 0; i < len; ++i)

p[i] = xfer(p[i]);

}

return len;

}

uint32_t transfer0(uint32_t data)

{

return !_selected || (_dbit >= 32) ? (uint32_t)ERROR : xfer(data);

}

};

class SPISettings

{

public:

SPISettings(void) : SPISettings(4000000, SPI_GPIO::MSBFIRST, SPI_GPIO::MODE0)

{

}

SPISettings(long speed, SPI_GPIO::BITORDER bitOrder, SPI_GPIO::MODE dataMode, int dataBit = 8, long delay = 1000)

: _speed(speed), _bitOrder(bitOrder), _dataMode(dataMode), _dataBit(dataBit), _delay(delay)

{

}

virtual ~SPISettings(void)

{

}

private:

long _speed;

SPI_GPIO::BITORDER _bitOrder;

SPI_GPIO::MODE _dataMode;

int _dataBit;

long _delay;

friend class SPIClass;

};

class SPIClass : public SPI_GPIO

{

public:

SPIClass(RP1_GPIO &gpio, int sclk, int mosi, int miso, const int *cspins = nullptr, size_t count = 0)

: SPI_GPIO(gpio, sclk, mosi, miso, cspins, count)

{

}

SPIClass(RP1_GPIO &gpio, int sclk, int mosi, int miso, size_t count, ...)

: SPIClass(gpio, sclk, mosi, miso)

{

va_list ap;

va_start(ap, count);

setupCS(ap, count);

va_end(ap);

}

SPIClass(RP1_GPIO &gpio, int sclk, int mosi, int miso, std::initializer_list<int> cslist)

: SPIClass(gpio, sclk, mosi, miso)

{

setupCS(cslist);

}

virtual ~SPIClass(void)

{

}

void begin(void)

{

}

void end(void)

{

}

inline void beginTransaction(SPISettings &settings)

{

SPI_GPIO::begin(settings._dataMode, settings._speed, settings._dataBit, settings._bitOrder, settings._delay);

}

inline void endTransaction(void)

{

}

inline uint32_t transfer(uint32_t data)

{

return SPI_GPIO::transfer(data);

}

inline void transfer(void *buf, size_t count)

{

SPI_GPIO::transfer(buf, count);

}

};

投稿者: researcher

Raspberry Pi 5 のSoftware-SPI libraryを作ってみた。