Microchip AVR8 用のライブラリを自作する。(SPI)

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 */
#define SPI_SS2  Port::PA4
#define SPI_SS3  Port::PA5

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();

　/* multi slave select */
  /* init pin (setup pin mode) */
  spi0.slave(SPI_SS2);
  spi0.slave(SPI_SS3, true);
  /* select SS2 */
  spi0.slave(SPI_SS2);
  spi0.select();
  ...
  spi0.deselect();
  /* select SS3 */
  spi0.slave(SPI_SS3, true);
  spi0.select();
  ...
  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 */

#define SPI_SS2 Port::PA4

#define SPI_SS3 Port::PA5

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();

　/* multi slave select */

/* init pin (setup pin mode) */

spi0.slave(SPI_SS2);

spi0.slave(SPI_SS3, true);

/* select SS2 */

spi0.slave(SPI_SS2);

spi0.select();

...

spi0.deselect();

/* select SS3 */

spi0.slave(SPI_SS3, true);

spi0.select();

...

spi0.deselect();

return 0;

}

【修正履歴】
2025-12-15
マルチ・スレーブ対応の仕様変更。slave()を追加しチップセレクトピンを極性付きで初期化できるように改良。

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), _ah(false)
    {
      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 slave(Port::PIN cs = Port::PNC, bool ah = false)
    {
      if (_ss != cs)
      {
        _cs = cs;
        _ah = ah;
        if (cs != Port::PNC)
          Port::pinMode(cs, Port::OUTPUT, ah ? Port::LOW : Port::HIGH);
      }
    }

    void select(void)
    {
      Port::digitalWrite(_ss, Port::LOW);
      if (_cs != Port::PNC)
        Port::digitalWrite(_cs, _ah ? Port::HIGH : Port::LOW);
      delay();
    }

    void deselect(void)
    {
      delay();
      if (_cs != Port::PNC)
        Port::digitalWrite(_cs, _ah ? Port::LOW : 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;
    bool      _ah;
    uint16_t  _delay;

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

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

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), _ah(false)

{

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 slave(Port::PIN cs = Port::PNC, bool ah = false)

{

if (_ss != cs)

{

_cs = cs;

_ah = ah;

if (cs != Port::PNC)

Port::pinMode(cs, Port::OUTPUT, ah ? Port::LOW : Port::HIGH);

}

void select(void)

{

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

if (_cs != Port::PNC)

Port::digitalWrite(_cs, _ah ? Port::HIGH : Port::LOW);

delay();

}

void deselect(void)

{

delay();

if (_cs != Port::PNC)

Port::digitalWrite(_cs, _ah ? Port::LOW : 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;

bool _ah;

uint16_t _delay;

void delay(void)

{

if (_delay)

_delay_loop_2(_delay);

}

};

コメントを残す コメントをキャンセル

コメントを残すコメントをキャンセル