Arduinoプログラミング手法－(4)USI(Universal Serial Interface)によるSPI実装

調べて見るとUSIを提供しているMCUがそれなりにあった。既に廃品種になってるものがあることから以外に古くから提供されていたようである。

ATA6616C, ATA6617C, ATA664251
ATmega165, ATmega169, ATmega325, ATmega329, ATmega645, ATmega649
ATmega3250, ATmega3290, ATmega6450, ATmega6490
ATtiny1634, ATtiny2313, ATtiny2313A, ATtiny4313
ATtiny24, ATtiny44, ATtiny84, ATtiny24A, ATtiny44A, ATtiny84A
ATtiny43U, ATtiny26, ATtiny25, ATtiny45, ATtiny85
ATtiny87, ATtiny167, ATtiny261, ATtiny461, ATtiny861

USI自体は同じ仕様であるが、MCUにより入出力ポートの割り当てや、次回に紹介するTWIのISR名が違うようなのでまずはその違いを吸収するためのヘッダーファイルを作成。

【SPI/TWI共通ヘッダーファイル】

#ifndef _USIPORTS_H
#define _USIPORTS_H

#define USI_PORT_HIGH(p) (USI_PORT(p##_X) |=  _BV(p##_N))
#define USI_PORT_LOW(p)  (USI_PORT(p##_X) &= ~_BV(p##_N))
#define USI_PORT_INV(p)  (USI_PIN(p##_X)  |=  _BV(p##_N))
#define USI_PORT_IN(p)   (USI_PIN(p##_X)  &   _BV(p##_N))
#define USI_DDR_OUT(p)   (USI_DDR(p##_X)  |=  _BV(p##_N))
#define USI_DDR_IN(p)    (USI_DDR(p##_X)  &= ~_BV(p##_N))

#define USI_PORT(p) USI_PORT_REG(p)
#define USI_PIN(p)  USI_PIN_REG(p)
#define USI_DDR(p)  USI_DDR_REG(p)

#define USI_PORT_REG(p) PORT##p
#define USI_PIN_REG(p)  PIN##p
#define USI_DDR_REG(p)  DDR##p

#define USI_SDA_X USI_DI_X
#define USI_SDA_N USI_DI_N
#define USI_SCL_X USI_USCK_X
#define USI_SCL_N USI_USCK_N

#ifndef USI_PIN_POSITION
#define USI_PIN_POSITION 0
#endif

#if defined(__AVR_ATmega165__ ) || defined(__AVR_ATmega165A__ ) || defined(__AVR_ATmega165P__ ) || defined(__AVR_ATmega165PA__ ) || \
    defined(__AVR_ATmega169__ ) || defined(__AVR_ATmega169A__ ) || defined(__AVR_ATmega169P__ ) || defined(__AVR_ATmega169PA__ ) || \
    defined(__AVR_ATmega325__ ) || defined(__AVR_ATmega325A__ ) || defined(__AVR_ATmega325P__ ) || defined(__AVR_ATmega325PA__ ) || \
    defined(__AVR_ATmega3250__) || defined(__AVR_ATmega3250A__) || defined(__AVR_ATmega3250P__) || defined(__AVR_ATmega3250PA__) || \
    defined(__AVR_ATmega329__ ) || defined(__AVR_ATmega329A__ ) || defined(__AVR_ATmega329P__ ) || defined(__AVR_ATmega329PA__ ) || \
    defined(__AVR_ATmega3290__) || defined(__AVR_ATmega3290A__) || defined(__AVR_ATmega3290P__) || defined(__AVR_ATmega3290PA__) || \
    defined(__AVR_ATmega645__ ) || defined(__AVR_ATmega645A__ ) || defined(__AVR_ATmega645P__ ) || \
    defined(__AVR_ATmega6450__) || defined(__AVR_ATmega6450A__) || defined(__AVR_ATmega6450P__) || \
    defined(__AVR_ATmega649__ ) || defined(__AVR_ATmega649A__ ) || defined(__AVR_ATmega649P__ ) || \
    defined(__AVR_ATmega6490__) || defined(__AVR_ATmega6490A__) || defined(__AVR_ATmega6490P__)

  #define USI_DI_X   E
  #define USI_DI_N   5
  #define USI_DO_X   E
  #define USI_DO_N   6
  #define USI_USCK_X E
  #define USI_USCK_N 4

  #define USI_OVF_vect USI_OVERFLOW_vect

#elif defined(__AVR_ATtiny2313__) || defined(__AVR_ATtiny2313A__) || defined(__AVR_ATtiny4313__)

  #define USI_DI_X   B
  #define USI_DI_N   5
  #define USI_DO_X   B
  #define USI_DO_N   6
  #define USI_USCK_X B
  #define USI_USCK_N 7

  #define USI_OVF_vect USI_OVERFLOW_vect

#elif defined(__AVR_ATtiny24A__) || defined(__AVR_ATtiny44A__) || defined(__AVR_ATtiny84A__)

  #define USI_DI_X   A
  #define USI_DI_N   6
  #define USI_DO_X   A
  #define USI_DO_N   5
  #define USI_USCK_X A
  #define USI_USCK_N 4

  #define USI_START_vect USI_STR_vect

#elif defined(__AVR_ATtiny24__) || defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__)

  #define USI_DI_X   A
  #define USI_DI_N   6
  #define USI_DO_X   A
  #define USI_DO_N   5
  #define USI_USCK_X A
  #define USI_USCK_N 4

#elif defined(__AVR_ATtiny1634__)

  #define USI_DI_X   B
  #define USI_DI_N   1
  #define USI_DO_X   B
  #define USI_DO_N   2
  #define USI_USCK_X C
  #define USI_USCK_N 1

#elif defined(__AVR_ATtiny43U__)

  #define USI_DI_X   B
  #define USI_DI_N   4
  #define USI_DO_X   B
  #define USI_DO_N   5
  #define USI_USCK_X B
  #define USI_USCK_N 6

#elif defined(__AVR_ATtiny26__)

  #define USI_DI_X   B
  #define USI_DI_N   0
  #define USI_DO_X   B
  #define USI_DO_N   1
  #define USI_USCK_X B
  #define USI_USCK_N 2

  #define USI_START_vect USI_STRT_vect

#elif defined(__AVR_ATtiny25__) || defined(__AVR_ATtiny45__) || defined(__AVR_ATtiny85__)

  #define USI_DI_X   B
  #define USI_DI_N   0
  #define USI_DO_X   B
  #define USI_DO_N   1
  #define USI_USCK_X B
  #define USI_USCK_N 2

#elif defined(__AVR_ATtiny261__) || defined(__AVR_ATtiny461__) || defined(__AVR_ATtiny861__)

  #if (USI_PIN_POSITION == 0)
    #define USI_DI_X   B
    #define USI_DI_N   0
    #define USI_DO_X   B
    #define USI_DO_N   1
    #define USI_USCK_X B
    #define USI_USCK_N 2
  #else
    #define USI_DI_X   A
    #define USI_DI_N   0
    #define USI_DO_X   A
    #define USI_DO_N   1
    #define USI_USCK_X A
    #define USI_USCK_N 2
  #endif

#elif defined(__AVR_ATtiny87__ ) || defined(__AVR_ATtiny167__) || \
      defined(__AVR_ATA6616C__ ) || defined(__AVR_ATA6617C__ ) || defined(__AVR_ATA664251__)

  #if (USI_PIN_POSITION == 0)
    #define USI_DI_X   B
    #define USI_DI_N   0
    #define USI_DO_X   B
    #define USI_DO_N   1
    #define USI_USCK_X B
    #define USI_USCK_N 2
  #else
    #define USI_DI_X   A
    #define USI_DI_N   4
    #define USI_DO_X   A
    #define USI_DO_N   2
    #define USI_USCK_X A
    #define USI_USCK_N 5
  #endif

#endif

#endif //_USIPORTS_H

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

#ifndef _USIPORTS_H

#define _USIPORTS_H

#define USI_PORT_HIGH(p) (USI_PORT(p##_X) |= _BV(p##_N))

#define USI_PORT_LOW(p) (USI_PORT(p##_X) &= ~_BV(p##_N))

#define USI_PORT_INV(p) (USI_PIN(p##_X) |= _BV(p##_N))

#define USI_PORT_IN(p) (USI_PIN(p##_X) & _BV(p##_N))

#define USI_DDR_OUT(p) (USI_DDR(p##_X) |= _BV(p##_N))

#define USI_DDR_IN(p) (USI_DDR(p##_X) &= ~_BV(p##_N))

#define USI_PORT(p) USI_PORT_REG(p)

#define USI_PIN(p) USI_PIN_REG(p)

#define USI_DDR(p) USI_DDR_REG(p)

#define USI_PORT_REG(p) PORT##p

#define USI_PIN_REG(p) PIN##p

#define USI_DDR_REG(p) DDR##p

#define USI_SDA_X USI_DI_X

#define USI_SDA_N USI_DI_N

#define USI_SCL_X USI_USCK_X

#define USI_SCL_N USI_USCK_N

#ifndef USI_PIN_POSITION

#define USI_PIN_POSITION 0

#endif

#if defined(__AVR_ATmega165__ ) || defined(__AVR_ATmega165A__ ) || defined(__AVR_ATmega165P__ ) || defined(__AVR_ATmega165PA__ ) || \

defined(__AVR_ATmega169__ ) || defined(__AVR_ATmega169A__ ) || defined(__AVR_ATmega169P__ ) || defined(__AVR_ATmega169PA__ ) || \

defined(__AVR_ATmega325__ ) || defined(__AVR_ATmega325A__ ) || defined(__AVR_ATmega325P__ ) || defined(__AVR_ATmega325PA__ ) || \

defined(__AVR_ATmega3250__) || defined(__AVR_ATmega3250A__) || defined(__AVR_ATmega3250P__) || defined(__AVR_ATmega3250PA__) || \

defined(__AVR_ATmega329__ ) || defined(__AVR_ATmega329A__ ) || defined(__AVR_ATmega329P__ ) || defined(__AVR_ATmega329PA__ ) || \

defined(__AVR_ATmega3290__) || defined(__AVR_ATmega3290A__) || defined(__AVR_ATmega3290P__) || defined(__AVR_ATmega3290PA__) || \

defined(__AVR_ATmega645__ ) || defined(__AVR_ATmega645A__ ) || defined(__AVR_ATmega645P__ ) || \

defined(__AVR_ATmega6450__) || defined(__AVR_ATmega6450A__) || defined(__AVR_ATmega6450P__) || \

defined(__AVR_ATmega649__ ) || defined(__AVR_ATmega649A__ ) || defined(__AVR_ATmega649P__ ) || \

defined(__AVR_ATmega6490__) || defined(__AVR_ATmega6490A__) || defined(__AVR_ATmega6490P__)

#define USI_DI_X E

#define USI_DI_N 5

#define USI_DO_X E

#define USI_DO_N 6

#define USI_USCK_X E

#define USI_USCK_N 4

#define USI_OVF_vect USI_OVERFLOW_vect

#elif defined(__AVR_ATtiny2313__) || defined(__AVR_ATtiny2313A__) || defined(__AVR_ATtiny4313__)

#define USI_DI_X B

#define USI_DI_N 5

#define USI_DO_X B

#define USI_DO_N 6

#define USI_USCK_X B

#define USI_USCK_N 7

#define USI_OVF_vect USI_OVERFLOW_vect

#elif defined(__AVR_ATtiny24A__) || defined(__AVR_ATtiny44A__) || defined(__AVR_ATtiny84A__)

#define USI_DI_X A

#define USI_DI_N 6

#define USI_DO_X A

#define USI_DO_N 5

#define USI_USCK_X A

#define USI_USCK_N 4

#define USI_START_vect USI_STR_vect

#elif defined(__AVR_ATtiny24__) || defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__)

#define USI_DI_X A

#define USI_DI_N 6

#define USI_DO_X A

#define USI_DO_N 5

#define USI_USCK_X A

#define USI_USCK_N 4

#elif defined(__AVR_ATtiny1634__)

#define USI_DI_X B

#define USI_DI_N 1

#define USI_DO_X B

#define USI_DO_N 2

#define USI_USCK_X C

#define USI_USCK_N 1

#elif defined(__AVR_ATtiny43U__)

#define USI_DI_X B

#define USI_DI_N 4

#define USI_DO_X B

#define USI_DO_N 5

#define USI_USCK_X B

#define USI_USCK_N 6

#elif defined(__AVR_ATtiny26__)

#define USI_DI_X B

#define USI_DI_N 0

#define USI_DO_X B

#define USI_DO_N 1

#define USI_USCK_X B

#define USI_USCK_N 2

#define USI_START_vect USI_STRT_vect

#elif defined(__AVR_ATtiny25__) || defined(__AVR_ATtiny45__) || defined(__AVR_ATtiny85__)

#define USI_DI_X B

#define USI_DI_N 0

#define USI_DO_X B

#define USI_DO_N 1

#define USI_USCK_X B

#define USI_USCK_N 2

#elif defined(__AVR_ATtiny261__) || defined(__AVR_ATtiny461__) || defined(__AVR_ATtiny861__)

#if (USI_PIN_POSITION == 0)

#define USI_DI_X B

#define USI_DI_N 0

#define USI_DO_X B

#define USI_DO_N 1

#define USI_USCK_X B

#define USI_USCK_N 2

#else

#define USI_DI_X A

#define USI_DI_N 0

#define USI_DO_X A

#define USI_DO_N 1

#define USI_USCK_X A

#define USI_USCK_N 2

#endif

#elif defined(__AVR_ATtiny87__ ) || defined(__AVR_ATtiny167__) || \

defined(__AVR_ATA6616C__ ) || defined(__AVR_ATA6617C__ ) || defined(__AVR_ATA664251__)

#if (USI_PIN_POSITION == 0)

#define USI_DI_X B

#define USI_DI_N 0

#define USI_DO_X B

#define USI_DO_N 1

#define USI_USCK_X B

#define USI_USCK_N 2

#else

#define USI_DI_X A

#define USI_DI_N 4

#define USI_DO_X A

#define USI_DO_N 2

#define USI_USCK_X A

#define USI_USCK_N 5

#endif

#endif //_USIPORTS_H

SPIマスタークラスのテンプレート・クラス実装。他サイトで紹介されているものとの相違点は、SPIクロック指定ができることと、複数スレーブにも対応可能となっていること。

【SPIマスタークラス】

#ifndef _USISPI_H
#define _USISPI_H

#include <util/delay_basic.h>
#include "USIPORTS.h"

#define USISPI_1M 1
#define USISPI_2M 2
#define USISPI_4M 4
#define USISPI_8M 8

#define USISPI_CSN_NONE 0xFF

typedef void (*USISPI_CSN_PROC)(bool enable, uint8_t addr);

#define USISPI_DELAY(t) { \
  if ((t) <= 768 / (F_CPU / 1000000)) \
    _delay_loop_1((uint8_t)((t) * (F_CPU / 1000000) * 256 / 768)); \
  else \
    _delay_loop_2((uint16_t)((t) * (F_CPU / 1000000) * 65536.0 / 262100)); \
}
#define USISPI_NOP() __asm__ __volatile__ ("nop" "\n\t"::)

template<uint8_t SPI_CLK = USISPI_8M, uint8_t CSN_PIN = USISPI_CSN_NONE, uint8_t ENABLE_DELAY = 20, uint8_t DISABLE_DELAY = 50>
class USISPI
{
  private:
    USISPI_CSN_PROC _csn_proc;

  public:
    USISPI()
    : _csn_proc(0)
    {
    }

    void begin()
    {
      USI_DDR_IN(USI_DI);
      USI_PORT_HIGH(USI_DO);
      USI_PORT_HIGH(USI_USCK);
      USI_DDR_OUT(USI_DO);
      USI_DDR_OUT(USI_USCK);
      if (CSN_PIN != USISPI_CSN_NONE)
      {
        digitalWrite(CSN_PIN, HIGH);
        pinMode(CSN_PIN, OUTPUT);
      }
    }

    void end()
    {
      USI_DDR_IN(USI_DO);
      USI_DDR_IN(USI_USCK);
      USI_PORT_LOW(USI_DO);
      USI_PORT_LOW(USI_USCK);
      if (CSN_PIN != USISPI_CSN_NONE)
      {
        pinMode(CSN_PIN, INPUT);
        digitalWrite(CSN_PIN, LOW);
      }
    }

    void setCallback(USISPI_CSN_PROC proc)
    {
      _csn_proc = proc;
    }

    uint8_t write(const uint8_t *buf, uint8_t len, uint8_t addr = CSN_PIN)
    {
      cs(true, addr);
      for (uint8_t i = 0; i < len; ++i)
        transfer(*buf++);
      cs(false, addr);
      return len;
    }

    uint8_t read(uint8_t *buf, uint8_t len, uint8_t addr = CSN_PIN)
    {
      cs(true, addr);
      for (uint8_t i = 0; i < len; ++i)
        *buf++ = transfer(0xFF);
      cs(false, addr);
      return len;
    }

    uint8_t writeAndRead(uint8_t *wbuf, uint8_t wlen, uint8_t *rbuf, uint8_t rlen, uint8_t addr = CSN_PIN)
    {
      uint8_t i;
      cs(true, addr);
      for (i = 0; i < wlen; ++i)
        transfer(*wbuf++);
      for (i = 0; i < rlen; ++i)
        *rbuf++ = transfer(0xFF);
      cs(false, addr);
      return rlen;
    }

    void cs(boolean enable, uint8_t addr = CSN_PIN)
    {
      //
      // chip select
      //
      if (addr != USISPI_CSN_NONE)
      {
        if (enable)
        {
          USI_PORT_LOW(USI_USCK);
          if (_csn_proc)
            (*_csn_proc)(enable, addr);
          else
            digitalWrite(addr, LOW);
        }
        else
        {
          if (_csn_proc)
            (*_csn_proc)(enable, addr);
          else
            digitalWrite(addr, HIGH);
          USI_PORT_HIGH(USI_USCK);
        }
      }
      //
      // chip select from special logic with USCK
      //
      //   nrf24l01+ control with 3 ATtiny85 pins
      //   http://nerdralph.blogspot.jp/2014/01/nrf24l01-control-with-3-attiny85-pins.html
      //
      else
      {
        if (enable)
        {
          USI_PORT_LOW(USI_USCK);
          USISPI_DELAY(ENABLE_DELAY);
        }
        else
        {
          USI_PORT_HIGH(USI_USCK);
          USISPI_DELAY(DISABLE_DELAY);
        }
      }
    }

    uint8_t transfer(uint8_t txd)
    {
      USIDR = txd;
      //
      // FCK / 16
      //
      if (SPI_CLK == (F_CPU / 1000000 / 16))
      {
        const uint8_t cr = _BV(USIWM0) | _BV(USICS1) | _BV(USICLK) | _BV(USITC);
        USISR = _BV(USIOIF);
        do
        {
          USICR = cr;
          USISPI_NOP();
          USISPI_NOP();
          USISPI_NOP();
          USISPI_NOP();
        }
        while (!(USISR & _BV(USIOIF)));
      }
      //
      // FCK / 8
      //
      else if (SPI_CLK == (F_CPU / 1000000 / 8))
      {
        const uint8_t cr = _BV(USIWM0) | _BV(USICS1) | _BV(USICLK) | _BV(USITC);
        USISR = _BV(USIOIF);
        do
          USICR = cr;
        while (!(USISR & _BV(USIOIF)));
      }
      //
      // FCK / 4
      //
      else if (SPI_CLK == (F_CPU / 1000000 / 4))
      {
        const uint8_t cr = _BV(USIWM0) | _BV(USICS1) | _BV(USITC);
        USICR = cr;
        USISPI_NOP();
        USICR = cr;
        USISPI_NOP();
        USICR = cr;
        USISPI_NOP();
        USICR = cr;
        USISPI_NOP();
        USICR = cr;
        USISPI_NOP();
        USICR = cr;
        USISPI_NOP();
        USICR = cr;
        USISPI_NOP();
        USICR = cr;
        USISPI_NOP();
        USICR = cr;
        USISPI_NOP();
        USICR = cr;
        USISPI_NOP();
        USICR = cr;
        USISPI_NOP();
        USICR = cr;
        USISPI_NOP();
        USICR = cr;
        USISPI_NOP();
        USICR = cr;
        USISPI_NOP();
        USICR = cr;
        USISPI_NOP();
        USICR = cr;
        USISPI_NOP();
      }
      //
      // FCK / 2. default.
      //
      else
      {
        const uint8_t cr0 = _BV(USIWM0) | _BV(USICLK) | _BV(USITC);
        const uint8_t cr1 = _BV(USIWM0) | _BV(USITC);
        USICR = cr0;
        USICR = cr1;
        USICR = cr0;
        USICR = cr1;
        USICR = cr0;
        USICR = cr1;
        USICR = cr0;
        USICR = cr1;
        USICR = cr0;
        USICR = cr1;
        USICR = cr0;
        USICR = cr1;
        USICR = cr0;
        USICR = cr1;
        USICR = cr0;
        USICR = cr1;
      }
      return USIDR;
    }
};

#endif // _USISPI_H

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

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

#ifndef _USISPI_H

#define _USISPI_H

#include <util/delay_basic.h>

#include "USIPORTS.h"

#define USISPI_1M 1

#define USISPI_2M 2

#define USISPI_4M 4

#define USISPI_8M 8

#define USISPI_CSN_NONE 0xFF

typedef void (*USISPI_CSN_PROC)(bool enable, uint8_t addr);

#define USISPI_DELAY(t) { \

if ((t) <= 768 / (F_CPU / 1000000)) \

_delay_loop_1((uint8_t)((t) * (F_CPU / 1000000) * 256 / 768)); \

else \

_delay_loop_2((uint16_t)((t) * (F_CPU / 1000000) * 65536.0 / 262100)); \

}

#define USISPI_NOP() __asm__ __volatile__ ("nop" "\n\t"::)

template<uint8_t SPI_CLK = USISPI_8M, uint8_t CSN_PIN = USISPI_CSN_NONE, uint8_t ENABLE_DELAY = 20, uint8_t DISABLE_DELAY = 50>

class USISPI

{

private:

USISPI_CSN_PROC _csn_proc;

public:

USISPI()

: _csn_proc(0)

{

}

void begin()

{

USI_DDR_IN(USI_DI);

USI_PORT_HIGH(USI_DO);

USI_PORT_HIGH(USI_USCK);

USI_DDR_OUT(USI_DO);

USI_DDR_OUT(USI_USCK);

if (CSN_PIN != USISPI_CSN_NONE)

{

digitalWrite(CSN_PIN, HIGH);

pinMode(CSN_PIN, OUTPUT);

}

void end()

{

USI_DDR_IN(USI_DO);

USI_DDR_IN(USI_USCK);

USI_PORT_LOW(USI_DO);

USI_PORT_LOW(USI_USCK);

if (CSN_PIN != USISPI_CSN_NONE)

{

pinMode(CSN_PIN, INPUT);

digitalWrite(CSN_PIN, LOW);

}

void setCallback(USISPI_CSN_PROC proc)

{

_csn_proc = proc;

}

uint8_t write(const uint8_t *buf, uint8_t len, uint8_t addr = CSN_PIN)

{

cs(true, addr);

for (uint8_t i = 0; i < len; ++i)

transfer(*buf++);

cs(false, addr);

return len;

}

uint8_t read(uint8_t *buf, uint8_t len, uint8_t addr = CSN_PIN)

{

cs(true, addr);

for (uint8_t i = 0; i < len; ++i)

*buf++ = transfer(0xFF);

cs(false, addr);

return len;

}

uint8_t writeAndRead(uint8_t *wbuf, uint8_t wlen, uint8_t *rbuf, uint8_t rlen, uint8_t addr = CSN_PIN)

{

uint8_t i;

cs(true, addr);

for (i = 0; i < wlen; ++i)

transfer(*wbuf++);

for (i = 0; i < rlen; ++i)

*rbuf++ = transfer(0xFF);

cs(false, addr);

return rlen;

}

void cs(boolean enable, uint8_t addr = CSN_PIN)

{

// chip select

if (addr != USISPI_CSN_NONE)

{

if (enable)

{

USI_PORT_LOW(USI_USCK);

if (_csn_proc)

(*_csn_proc)(enable, addr);

else

digitalWrite(addr, LOW);

}

else

{

if (_csn_proc)

(*_csn_proc)(enable, addr);

else

digitalWrite(addr, HIGH);

USI_PORT_HIGH(USI_USCK);

}

// chip select from special logic with USCK

// nrf24l01+ control with 3 ATtiny85 pins

// http://nerdralph.blogspot.jp/2014/01/nrf24l01-control-with-3-attiny85-pins.html

else

{

if (enable)

{

USI_PORT_LOW(USI_USCK);

USISPI_DELAY(ENABLE_DELAY);

}

else

{

USI_PORT_HIGH(USI_USCK);

USISPI_DELAY(DISABLE_DELAY);

}

uint8_t transfer(uint8_t txd)

{

USIDR = txd;

// FCK / 16

if (SPI_CLK == (F_CPU / 1000000 / 16))

{

const uint8_t cr = _BV(USIWM0) | _BV(USICS1) | _BV(USICLK) | _BV(USITC);

USISR = _BV(USIOIF);

{

USICR = cr;

USISPI_NOP();

}

while (!(USISR & _BV(USIOIF)));

}

// FCK / 8

else if (SPI_CLK == (F_CPU / 1000000 / 8))

{

const uint8_t cr = _BV(USIWM0) | _BV(USICS1) | _BV(USICLK) | _BV(USITC);

USISR = _BV(USIOIF);

USICR = cr;

while (!(USISR & _BV(USIOIF)));

}

// FCK / 4

else if (SPI_CLK == (F_CPU / 1000000 / 4))

{

const uint8_t cr = _BV(USIWM0) | _BV(USICS1) | _BV(USITC);

USICR = cr;

USISPI_NOP();

USICR = cr;

USISPI_NOP();

USICR = cr;

USISPI_NOP();

USICR = cr;

USISPI_NOP();

USICR = cr;

USISPI_NOP();

USICR = cr;

USISPI_NOP();

USICR = cr;

USISPI_NOP();

USICR = cr;

USISPI_NOP();

USICR = cr;

USISPI_NOP();

USICR = cr;

USISPI_NOP();

USICR = cr;

USISPI_NOP();

USICR = cr;

USISPI_NOP();

USICR = cr;

USISPI_NOP();

USICR = cr;

USISPI_NOP();

USICR = cr;

USISPI_NOP();

USICR = cr;

USISPI_NOP();

}

// FCK / 2. default.

else

{

const uint8_t cr0 = _BV(USIWM0) | _BV(USICLK) | _BV(USITC);

const uint8_t cr1 = _BV(USIWM0) | _BV(USITC);

USICR = cr0;

USICR = cr1;

USICR = cr0;

USICR = cr1;

USICR = cr0;

USICR = cr1;

USICR = cr0;

USICR = cr1;

USICR = cr0;

USICR = cr1;

USICR = cr0;

USICR = cr1;

USICR = cr0;

USICR = cr1;

USICR = cr0;

USICR = cr1;

}

return USIDR;

}

};

#endif // _USISPI_H

【標準的な使い方】

#include "USISPI.h"

#define SPI_CSN_PIN PB4

USISPI<USISPI_8M, SPI_CSN_PIN> spi;

void setup()
{
  spi.begin();
}

void loop()
{
  spi.write(...);
  spi.read(...);
  spi.writeAndRead(...);

  or

  spi.cs(true);
  spi.transfer(...);
  spi.cs(false);
}

#include "USISPI.h"

#define SPI_CSN_PIN PB4

USISPI<USISPI_8M, SPI_CSN_PIN> spi;

void setup()

{

spi.begin();

}

void loop()

{

spi.write(...);

spi.read(...);

spi.writeAndRead(...);

spi.cs(true);

spi.transfer(...);

spi.cs(false);

}

【複数スレーブ対応(1)】

#include "USISPI.h"

#define SPI_CSN_0_PIN PA0
#define SPI_CSN_1_PIN PA1
#define SPI_CSN_2_PIN PA2

USISPI<USISPI_8M> spi;

void setup()
{
  pinMode(SPI_CSN_0, OUTPUT);
  pinMode(SPI_CSN_1, OUTPUT);
  pinMode(SPI_CSN_2, OUTPUT);
  digitalWrite(SPI_CSN_0, HIGH);
  digitalWrite(SPI_CSN_1, HIGH);
  digitalWrite(SPI_CSN_2, HIGH);
  spi.begin();
}

void loop()
{
  spi.write(..., SPI_CSN_0);
  spi.read(..., SPI_CSN_1);
  spi.writeAndRead(..., SPI_CSN_2);

  or

  spi.cs(true, SPI_CSN_0);
  spi.transfer(...);
  spi.cs(false, SPI_CSN_0);
}

#include "USISPI.h"

#define SPI_CSN_0_PIN PA0

#define SPI_CSN_1_PIN PA1

#define SPI_CSN_2_PIN PA2

USISPI<USISPI_8M> spi;

void setup()

{

pinMode(SPI_CSN_0, OUTPUT);

pinMode(SPI_CSN_1, OUTPUT);

pinMode(SPI_CSN_2, OUTPUT);

digitalWrite(SPI_CSN_0, HIGH);

digitalWrite(SPI_CSN_1, HIGH);

digitalWrite(SPI_CSN_2, HIGH);

spi.begin();

}

void loop()

{

spi.write(..., SPI_CSN_0);

spi.read(..., SPI_CSN_1);

spi.writeAndRead(..., SPI_CSN_2);

spi.cs(true, SPI_CSN_0);

spi.transfer(...);

spi.cs(false, SPI_CSN_0);

}

【複数スレーブ対応(2)】

#include "USISPI.h"

#define SPI_CSN_0_PIN PA0
#define SPI_CSN_1_PIN PA1
#define SPI_CSN_2_PIN PA2
 
USISPI<USISPI_8M> spi;

void select_slave(bool enable, uint8_t addr)
{
  digitalWrite(addr, enable);
}

void setup()
{
  pinMode(SPI_CSN_0, OUTPUT);
  pinMode(SPI_CSN_1, OUTPUT);
  pinMode(SPI_CSN_2, OUTPUT);
  digitalWrite(SPI_CSN_0, HIGH);
  digitalWrite(SPI_CSN_1, HIGH);
  digitalWrite(SPI_CSN_2, HIGH);
  spi.begin();
  spi.setCallback(select_slave);
}
 
void loop()
{
  spi.write(..., SPI_CSN_0);
  spi.read(..., SPI_CSN_1);
  spi.writeAndRead(..., SPI_CSN_2);
 
  or
 
  spi.cs(true, SPI_CSN_0);
  spi.transfer(...);
  spi.cs(false, SPI_CSN_0);
}

#include "USISPI.h"

#define SPI_CSN_0_PIN PA0

#define SPI_CSN_1_PIN PA1

#define SPI_CSN_2_PIN PA2

USISPI<USISPI_8M> spi;

void select_slave(bool enable, uint8_t addr)

{

digitalWrite(addr, enable);

}

void setup()

{

pinMode(SPI_CSN_0, OUTPUT);

pinMode(SPI_CSN_1, OUTPUT);

pinMode(SPI_CSN_2, OUTPUT);

digitalWrite(SPI_CSN_0, HIGH);

digitalWrite(SPI_CSN_1, HIGH);

digitalWrite(SPI_CSN_2, HIGH);

spi.begin();

spi.setCallback(select_slave);

}

void loop()

{

spi.write(..., SPI_CSN_0);

spi.read(..., SPI_CSN_1);

spi.writeAndRead(..., SPI_CSN_2);

spi.cs(true, SPI_CSN_0);

spi.transfer(...);

spi.cs(false, SPI_CSN_0);

}

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