Sasapea's Lab

マスターモード専用のＳＰＩライブラリ。スレーブモードはやる気がでたらということで．．．(-_-;)

【サンプルコード (Microchip Studio)】

#include "avr8_spi.h"

#define SPI_SS   Port::PA0 /* for ATtiny202/402 */
#define SPI_MOSI Port::PA1 /* for ATtiny202/402 */
#define SPI_MISO Port::PA2 /* for ATtiny202/402 */
#define SPI_SCK  Port::PA3 /* for ATtiny202/402 */

Spi spi0(SPI0, SPI_MOSI, SPI_MISO, SPI_SCK, SPI_SS);

int main(void)
{
  sei();
  Clock::setup();

  /* SPI Mode 3, 4MHz, Delay 1us */
  spi0.begin(4000000);

  uint8_t wdata[8] = { ... };
  uint8_t rdata[8];

  /* write and read (exchange) */
  spi0.select();
  spi0.xfer(wdata, rdata, sizeof(wdata));
  spi0.deselect();

  /* write */
  spi0.select();
  spi0.write(wdata, sizeof(data);
  spi0.deselect();

  /* read */
  spi0.select();
  spi0.read(rdata, sizeof(data);
  spi0.deselect();

  return 0;
}

#include "avr8_spi.h"

#define SPI_SS Port::PA0 /* for ATtiny202/402 */

#define SPI_MOSI Port::PA1 /* for ATtiny202/402 */

#define SPI_MISO Port::PA2 /* for ATtiny202/402 */

#define SPI_SCK Port::PA3 /* for ATtiny202/402 */

Spi spi0(SPI0, SPI_MOSI, SPI_MISO, SPI_SCK, SPI_SS);

int main(void)

{

sei();

Clock::setup();

/* SPI Mode 3, 4MHz, Delay 1us */

spi0.begin(4000000);

uint8_t wdata[8] = { ... };

uint8_t rdata[8];

/* write and read (exchange) */

spi0.select();

spi0.xfer(wdata, rdata, sizeof(wdata));

spi0.deselect();

/* write */

spi0.select();

spi0.write(wdata, sizeof(data);

spi0.deselect();

/* read */

spi0.select();

spi0.read(rdata, sizeof(data);

spi0.deselect();

return 0;

}

【修正履歴】
2025-12-13
マルチ・スレーブ対応のためselect()に省略可能なチップセレクトピンを指定できるようにしてみた。但し、マスター動作のために本来のSSピン制御は必要であるためスルチスレーブで使うさいは本来のSSピンは未接続とし他のピンをチップセレクトとして使う必要がある。

2025-12-12
コンストラクタにMOSI/MISO/SCK/SSピン指定を追加。SS制御用のselect()/deselect()/を追加。

2025-12-11
バッファリングモードに対応。転送データ間の間隔が短くなった分だけ転送速度が速くなった。

【ライブラリ】

/*
  avr8_spi.h - SPI Driver for Microchip AVR8 Series
 
  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 <util/delay.h>
#include "avr8_config.h"
#include "avr8_clock.h"
#include "avr8_port.h"

#if   defined(SPI1)
#define SPI_MAX_CH 2
#elif defined(SPI0)
#define SPI_MAX_CH 1
#else
#define SPI_MAX_CH 0
#endif

class Spi
{
  public:

    /* SPI Mode select */
    typedef enum
    {
      MODE_0 = SPI_MODE_0_gc,  /* SPI Mode 0 */
      MODE_1 = SPI_MODE_1_gc,  /* SPI Mode 1 */
      MODE_2 = SPI_MODE_2_gc,  /* SPI Mode 2 */
      MODE_3 = SPI_MODE_3_gc,  /* SPI Mode 3 */
    } MODE;

    /* Prescaler select */
    typedef enum
    {
      PRESC_DIV2   = SPI_PRESC_DIV4_gc  | SPI_CLK2X_bm,  /* System Clock / 2 */
      PRESC_DIV4   = SPI_PRESC_DIV4_gc,                  /* System Clock / 4 */
      PRESC_DIV8   = SPI_PRESC_DIV16_gc | SPI_CLK2X_bm,  /* System Clock / 8 */
      PRESC_DIV16  = SPI_PRESC_DIV16_gc,                 /* System Clock / 16 */
      PRESC_DIV32  = SPI_PRESC_DIV64_gc | SPI_CLK2X_bm,  /* System Clock / 32 */
      PRESC_DIV64  = SPI_PRESC_DIV64_gc,                 /* System Clock / 64 */
      PRESC_DIV128 = SPI_PRESC_DIV128_gc,                /* System Clock / 128 */
    } PRESC;

    Spi(SPI_t& spi, Port::PIN mosi, Port::PIN miso, Port::PIN sck, Port::PIN ss) : _spi(&spi), _ss(ss), _cs(Port::PNC)
    {
      Port::pinMode(mosi, Port::OUTPUT);
      Port::pinMode(miso, Port::INPUT);
      Port::pinMode(sck , Port::OUTPUT);
      Port::pinMode(ss  , Port::OUTPUT, Port::HIGH);
    }

    /* virtual */ ~Spi(void)
    {
      end();
    }

    bool begin(uint32_t frq, MODE mode = MODE_3, uint16_t delay = 0)
    {
      if (frq)
      {
        static const uint8_t CLKDIV[] = { 2, 4, 8, 16, 32, 64, 128 };
        static const PRESC   PRESCS[] = { PRESC_DIV2, PRESC_DIV4, PRESC_DIV8, PRESC_DIV16, PRESC_DIV32, PRESC_DIV64, PRESC_DIV128 };
        uint32_t clk = Clock::frequency();
        uint32_t div = clk / frq;
        uint32_t dly = ((clk / 1000) * delay + 3999) / 4000;
        delay = dly <= 0xFFFF ? dly : 0xFFFF;
        for (uint8_t i = 0; i < sizeof(CLKDIV) / sizeof(CLKDIV[0]); ++i)
        {
          if (div <= CLKDIV[i])
          {
            begin(PRESCS[i], mode, delay);
            return true;
          }
        }
        begin(PRESCS[sizeof(PRESCS) / sizeof(PRESCS[0]) - 1], mode, delay);
      }
      return false;
    }

    void begin(PRESC presc, MODE mode, uint16_t delay = 0)
    {
      end();
      _delay = delay;
      _spi->INTCTRL = 0;
      _spi->CTRLB   = SPI_BUFEN_bm | SPI_SSD_bm | mode;
      _spi->CTRLA   = SPI_MASTER_bm | presc | SPI_ENABLE_bm;
    }

    void end(void)
    {
      _spi->CTRLA = 0;
    }

    void lsbfirst(bool enable = true)
    {
      _spi->CTRLA = (_spi->CTRLA & ~SPI_DORD_bm) | (enable ? SPI_DORD_bm : 0);
    }

    void select(Port::PIN cs = Port::PNC)
    {
      Port::digitalWrite(_ss, Port::LOW);
      if ((_cs = cs) != Port::PNC)
        Port::digitalWrite(cs, Port::LOW);
      delay();
    }

    void deselect(void)
    {
      delay();
      if (_cs != Port::PNC)
        Port::digitalWrite(_cs, Port::HIGH);
      Port::digitalWrite(_ss, Port::HIGH);
    }

    uint8_t xfer(uint8_t data)
    {
      _spi->DATA = data;
      while ((_spi->INTFLAGS & SPI_RXCIF_bm) == 0)
        continue;
      return _spi->DATA;
    }

    uint8_t read(void)
    {
      return xfer(0xFF);
    }

    void write(uint8_t data)
    {
      xfer(data);
    }

    void xfer(const void *wbuf, void *rbuf, size_t len)
    {
      if (len)
      {
        size_t wcnt = len;
        const uint8_t *wptr = (const uint8_t*)wbuf;
        uint8_t *rptr = (uint8_t*)rbuf;
        while (1)
        {
          uint8_t data, flags = _spi->INTFLAGS;
          if (flags & SPI_RXCIF_bm)
          {
            data = _spi->DATA;
            if (rptr)
              *rptr++ = data;
            if (--len == 0)
              break;
          }
          if (wcnt && (flags & SPI_DREIF_bm))
          {
            data = wptr ? *wptr++ : 0xFF;
            --wcnt;
            _spi->DATA = data;
          }
        }
      }
    }

    void read(void *buf, size_t len)
    {
      xfer(0, buf, len);
    }

    void write(const void *buf, size_t len)
    {
      xfer(buf, 0, len);
    }

  protected:

    SPI_t*    _spi;
    Port::PIN _ss;
    Port::PIN _cs;
    uint16_t  _delay;

    void delay(void)
    {
      if (_delay)
      _delay_loop_2(_delay);
    }
};

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avr8_spi.h - SPI Driver for Microchip AVR8 Series

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 <util/delay.h>

#include "avr8_config.h"

#include "avr8_clock.h"

#include "avr8_port.h"

#if defined(SPI1)

#define SPI_MAX_CH 2

#elif defined(SPI0)

#define SPI_MAX_CH 1

#else

#define SPI_MAX_CH 0

#endif

class Spi

{

public:

/* SPI Mode select */

typedef enum

{

MODE_0 = SPI_MODE_0_gc, /* SPI Mode 0 */

MODE_1 = SPI_MODE_1_gc, /* SPI Mode 1 */

MODE_2 = SPI_MODE_2_gc, /* SPI Mode 2 */

MODE_3 = SPI_MODE_3_gc, /* SPI Mode 3 */

} MODE;

/* Prescaler select */

typedef enum

{

PRESC_DIV2 = SPI_PRESC_DIV4_gc | SPI_CLK2X_bm, /* System Clock / 2 */

PRESC_DIV4 = SPI_PRESC_DIV4_gc, /* System Clock / 4 */

PRESC_DIV8 = SPI_PRESC_DIV16_gc | SPI_CLK2X_bm, /* System Clock / 8 */

PRESC_DIV16 = SPI_PRESC_DIV16_gc, /* System Clock / 16 */

PRESC_DIV32 = SPI_PRESC_DIV64_gc | SPI_CLK2X_bm, /* System Clock / 32 */

PRESC_DIV64 = SPI_PRESC_DIV64_gc, /* System Clock / 64 */

PRESC_DIV128 = SPI_PRESC_DIV128_gc, /* System Clock / 128 */

} PRESC;

Spi(SPI_t& spi, Port::PIN mosi, Port::PIN miso, Port::PIN sck, Port::PIN ss) : _spi(&spi), _ss(ss), _cs(Port::PNC)

{

Port::pinMode(mosi, Port::OUTPUT);

Port::pinMode(miso, Port::INPUT);

Port::pinMode(sck , Port::OUTPUT);

Port::pinMode(ss , Port::OUTPUT, Port::HIGH);

}

/* virtual */ ~Spi(void)

{

end();

}

bool begin(uint32_t frq, MODE mode = MODE_3, uint16_t delay = 0)

{

if (frq)

{

static const uint8_t CLKDIV[] = { 2, 4, 8, 16, 32, 64, 128 };

static const PRESC PRESCS[] = { PRESC_DIV2, PRESC_DIV4, PRESC_DIV8, PRESC_DIV16, PRESC_DIV32, PRESC_DIV64, PRESC_DIV128 };

uint32_t clk = Clock::frequency();

uint32_t div = clk / frq;

uint32_t dly = ((clk / 1000) * delay + 3999) / 4000;

delay = dly <= 0xFFFF ? dly : 0xFFFF;

for (uint8_t i = 0; i < sizeof(CLKDIV) / sizeof(CLKDIV[0]); ++i)

{

if (div <= CLKDIV[i])

{

begin(PRESCS[i], mode, delay);

return true;

}

begin(PRESCS[sizeof(PRESCS) / sizeof(PRESCS[0]) - 1], mode, delay);

}

return false;

}

void begin(PRESC presc, MODE mode, uint16_t delay = 0)

{

end();

_delay = delay;

_spi->INTCTRL = 0;

_spi->CTRLB = SPI_BUFEN_bm | SPI_SSD_bm | mode;

_spi->CTRLA = SPI_MASTER_bm | presc | SPI_ENABLE_bm;

}

void end(void)

{

_spi->CTRLA = 0;

}

void lsbfirst(bool enable = true)

{

_spi->CTRLA = (_spi->CTRLA & ~SPI_DORD_bm) | (enable ? SPI_DORD_bm : 0);

}

void select(Port::PIN cs = Port::PNC)

{

Port::digitalWrite(_ss, Port::LOW);

if ((_cs = cs) != Port::PNC)

Port::digitalWrite(cs, Port::LOW);

delay();

}

void deselect(void)

{

delay();

if (_cs != Port::PNC)

Port::digitalWrite(_cs, Port::HIGH);

Port::digitalWrite(_ss, Port::HIGH);

}

uint8_t xfer(uint8_t data)

{

_spi->DATA = data;

while ((_spi->INTFLAGS & SPI_RXCIF_bm) == 0)

continue;

return _spi->DATA;

}

uint8_t read(void)

{

return xfer(0xFF);

}

void write(uint8_t data)

{

xfer(data);

}

void xfer(const void *wbuf, void *rbuf, size_t len)

{

if (len)

{

size_t wcnt = len;

const uint8_t *wptr = (const uint8_t*)wbuf;

uint8_t *rptr = (uint8_t*)rbuf;

while (1)

{

uint8_t data, flags = _spi->INTFLAGS;

if (flags & SPI_RXCIF_bm)

{

data = _spi->DATA;

if (rptr)

*rptr++ = data;

if (--len == 0)

break;

}

if (wcnt && (flags & SPI_DREIF_bm))

{

data = wptr ? *wptr++ : 0xFF;

--wcnt;

_spi->DATA = data;

}

void read(void *buf, size_t len)

{

xfer(0, buf, len);

}

void write(const void *buf, size_t len)

{

xfer(buf, 0, len);

}

protected:

SPI_t* _spi;

Port::PIN _ss;

Port::PIN _cs;

uint16_t _delay;

void delay(void)

{

if (_delay)

_delay_loop_2(_delay);

}

};

投稿

Microchip AVR8 用のライブラリを自作する。(SPI)