2020年7月 – ページ 4

マックスシリーズ？第２弾はSPIライブラリだ。ＨＷとは比べ物にならないがＳＷ実装としては最速だと思う。
ライト＆リード動作の場合はビット当たり6サイクルかかるので16MHzクロックなら最大2.67Mbpsとなるがライトとリードを分離した実装であればビット当たり4サイクルまで高速化できるので16MHzクロックなら最大4Mbpsとなる。なお、F_CPU/6(16MHzなら2.67Mbps)を超える速度を指定した場合、write()/read()は実速度とは合わなくなることに注意してほしい。例えば、16MHzクロックで8Mbpsを指定した場合の実速度は4Mbpsであるが幅の狭いほうのパルスだけ見れば8MbpsであるのでSPIスレーブ側は8Mbps以上の転送速度に対応している必要があるということになる。F_CPU/2を指定したときに最大速度となる。

【仕様】
・速度 16MHz 10.4Kbps – 4Mbps(write/read), 2.67Mbps(transfer)
・マスターモード
・mode-0/1/2/3
・8-bit
・MSB-FIRST

【1Mbpsの波形】

【約4Mbpsの波形(16.5MHzクロックでの最大速度)】

【概要】

void begin(void)

1	void begin(void)

ライブラリを初期化する。

oid end(void)

1	oid end(void)

ライブラリを終了する。

uint8_t transfer(uint8_t data)

1	uint8_t transfer(uint8_t data)

１バイトを送受信する。(6サイクル)

void transfer(uint8_t *buf, uint8_t len)

1	void transfer(uint8_t *buf, uint8_t len)

複数バイトを送受信する。

void write(uint8_t data)

1	void write(uint8_t data)

１バイトを送信する。(4サイクル)

void write(uint8_t *buf, uint8_t len)

1	void write(uint8_t *buf, uint8_t len)

複数バイトを送信する。

uint8_t read(void)

1	uint8_t read(void)

１バイトを受信する。(4サイクル)

void read(uint8_t *buf, uint8_t len)

1	void read(uint8_t *buf, uint8_t len)

複数バイトを受信する。

【サンプル・スケッチ】

#include "maxspi.h"

#define SPI_MISO IOPORT_PIN('B', 0)
#define SPI_MOSI IOPORT_PIN('B', 1)
#define SPI_SCLK IOPORT_PIN('B', 2)
#define SPI_CS   IOPORT_PIN('B', 3)
#define MAXSPI MaxSPI<MAXSPI_MODE3, 1000000, SPI_MISO, SPI_MOSI, SPI_SCLK>

void setup(void)
{
  IOPORT::digitalWrite(SPI_CS, HIGH);
  IOPORT::pinMode(SPI_CS, OUTPUT);
  MAXSPI::begin();
}

void loop(void)
{
  IOPORT::digitalWrite(SPI_CS, LOW);
  MAXSPI::transfer('A');
  IOPORT::digitalWrite(SPI_CS, HIGH);
}

#include "maxspi.h"

#define SPI_MISO IOPORT_PIN('B', 0)

#define SPI_MOSI IOPORT_PIN('B', 1)

#define SPI_SCLK IOPORT_PIN('B', 2)

#define SPI_CS IOPORT_PIN('B', 3)

#define MAXSPI MaxSPI<MAXSPI_MODE3, 1000000, SPI_MISO, SPI_MOSI, SPI_SCLK>

void setup(void)

{

IOPORT::digitalWrite(SPI_CS, HIGH);

IOPORT::pinMode(SPI_CS, OUTPUT);

MAXSPI::begin();

}

void loop(void)

{

IOPORT::digitalWrite(SPI_CS, LOW);

MAXSPI::transfer('A');

IOPORT::digitalWrite(SPI_CS, HIGH);

}

【修正履歴】
2020-07-31
かなりバグってたっぽいので修正ついでにテンプレート・パラメタにSPIモードを追加し全MODE対応してみた。

2020-07-15
同じコードが生成されるので問題ないがMISO入力に対して正しくないポートマクロ名を指定していたので修正。

2020-07-10
インラインアセンブラの入出力パラメタの使い方が正しくなかったので修正。

【ライブラリ】

/*
  maxspi.h - High Speed SPI Library for AVR Series

  Speed: 16MHz 10.4K - 4M bps (2.6M bps)

  Exsample:

    #include "maxspi.h"

    #define SPI_MISO IOPORT_PIN('B', 0)
    #define SPI_MOSI IOPORT_PIN('B', 1)
    #define SPI_SCLK IOPORT_PIN('B', 2)
    #define SPI_CS   IOPORT_PIN('B', 3)
    #define MAXSPI MaxSpi<MAXSPI_MODE3, 1000000, SPI_MISO, SPI_MOSI, SPI_SCLK>

    void setup(void)
    {
      IOPORT::digitalWrite(SPI_CS, HIGH);
      IOPORT::pinMode(SPI_CS, OUTPUT);
      MAXSPI::begin();
    }

    void loop(void)
    {
      IOPORT::digitalWrite(SPI_CS, LOW);
      MAXSPI::transfer('A');
      IOPORT::digitalWrite(SPI_CS, HIGH);
    }

  Copyright (c) 2020 Sasapea's Lab. All right reserved.

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library 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
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General
  Public License along with this library; if not, write to the
  Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  Boston, MA  02111-1307  USA
*/
#ifndef __MAXSPI_H
#define __MAXSPI_H

#include "ioport.h"

#define MAXSPI_CPOL 1
#define MAXSPI_CPHA 2

typedef enum
{
  MAXSPI_MODE0 = 0,                         // CPOL = 0, CPHA = 0
  MAXSPI_MODE1 = MAXSPI_CPHA,               // CPOL = 0, CPHA = 1
  MAXSPI_MODE2 = MAXSPI_CPOL | MAXSPI_CPHA, // CPOL = 1, CPHA = 1
  MAXSPI_MODE3 = MAXSPI_CPOL,               // CPOL = 1, CPHA = 0
} MAXSPI_MODE;

#define MAXSPI_DELAY_CYCLE 3 // cycle of delay loop
#define MAXSPI_CLOCK_CYCLE 3 // cycle of bit assembly
#define MAXSPI_CLOCK_CYCLE ((float)F_CPU / SPEED / 2)
#define MAXSPI_SWCLK_CYCLE (int)(MAXSPI_CLOCK_CYCLE + 0.5)
#define MAXSPI_DELAY(n, c) \
  do \
  { \
    int   cycle = 0; \
    float error = MAXSPI_CLOCK_CYCLE - MAXSPI_SWCLK_CYCLE; \
    float round = (error < 0 ? -0.5 : 0.5); \
    error -= (int)error; \
    if (((int)(error * (n) + round) ^ (int)(error * ((n) + 1) + round)) & 1) \
      cycle += (error < 0 ? -1 : 1); \
    if ((cycle += MAXSPI_SWCLK_CYCLE - (c)) > 0) \
    { \
      if (cycle / MAXSPI_DELAY_CYCLE) \
        __asm__ volatile \
        ( \
          "ldi r22, %[_COUNT_]" "\n\t" \
          "1: dec r22"          "\n\t" \
          "brne 1b"             "\n\t" \
          : \
          : [_COUNT_] "M" (cycle / MAXSPI_DELAY_CYCLE) \
          : "r22" \
        ); \
      if ((cycle % MAXSPI_DELAY_CYCLE) > 0) \
        __asm__ volatile ("nop"); \
      if ((cycle % MAXSPI_DELAY_CYCLE) > 1) \
        __asm__ volatile ("nop"); \
    } \
  } \
  while (0)

#define MAXSPI_SHIFT(no, bit) \
  do \
  { \
    __asm__ volatile \
    ( \
      "out  %[_SCLK_], r25"       "\n\t" \
      "sbrc r23, %[_BPOS_]"       "\n\t" \
      "out  %[_MOSI_], r26"       "\n\t" \
      : \
      : [_SCLK_] "I" (_SFR_IO_ADDR(IOPORT_TGLREG(SCLK))) \
      , [_MOSI_] "I" (_SFR_IO_ADDR(IOPORT_TGLREG(MOSI))) \
      , [_BPOS_] "I" (bit) \
    ); \
    MAXSPI_DELAY(no, MAXSPI_CLOCK_CYCLE); \
  } \
  while (0)

#define MAXSPI_LATCH(no, bit) \
  do \
  { \
    __asm__ volatile \
    ( \
      "out  %[_SCLK_], r25"            "\n\t" \
      "sbic %[_MISO_], %[_POSI_]"      "\n\t" \
      "ori  %[_DATA_], 1 << %[_BPOS_]" "\n\t" \
      : [_DATA_] "=r" (data) \
      : [_SCLK_] "I" (_SFR_IO_ADDR(IOPORT_TGLREG(SCLK))) \
      , [_MISO_] "I" (_SFR_IO_ADDR(IOPORT_INREG(MISO))) \
      , [_POSI_] "I" (IOPORT_PINPOS(MISO)) \
      , [_BPOS_] "I" (bit) \
    ); \
    MAXSPI_DELAY(no, MAXSPI_CLOCK_CYCLE); \
  } \
  while (0)

#define MAXSPI_CLOCK(no) \
  do \
  { \
    __asm__ volatile \
    ( \
      "out  %[_SCLK_], r25"       "\n\t" \
      : \
      : [_SCLK_] "I" (_SFR_IO_ADDR(IOPORT_TGLREG(SCLK))) \
    ); \
    MAXSPI_DELAY(no, 1); \
  } \
  while (0)

template<MAXSPI_MODE MODE, uint32_t SPEED, uint8_t MISO, uint8_t MOSI, uint8_t SCLK>
class MaxSpi
{
  public:

    static void begin(void)
    {
      IOPORT::digitalWrite(SCLK, MODE & MAXSPI_CPOL ? HIGH : LOW);
      IOPORT::pinMode(SCLK, OUTPUT);
      IOPORT::pinMode(MOSI, OUTPUT);
      IOPORT::pinMode(MISO, INPUT );
    }

    static void end(void)
    {
      IOPORT::pinMode(SCLK, INPUT);
      IOPORT::pinMode(MOSI, INPUT);
    }

    static uint8_t transfer(uint8_t data)
    {
      __asm__ volatile
      (
        "mov  r23, %[_DATA_]"       "\n\t"
        "clc"                       "\n\t"
        "sbic %[_MOSI_], %[_POSO_]" "\n\t"
        "sec"                       "\n\t"
        "ror  r23"                  "\n\t"
        "eor  r23, %[_DATA_]"       "\n\t"
        "clr  %[_DATA_]"            "\n\t"
        "ldi  r26, 1 << %[_POSO_]"  "\n\t"
        "ldi  r25, 1 << %[_POSC_]"  "\n\t"
        : [_DATA_] "=r" (data)
        : [_MOSI_] "I" (_SFR_IO_ADDR(IOPORT_OUTREG(MOSI)))
        , [_POSO_] "I" (IOPORT_PINPOS(MOSI))
        , [_POSC_] "I" (IOPORT_PINPOS(SCLK))
        : "r23", "r25", "r26"
      );
      if (MODE & MAXSPI_CPHA) // CPHA = 1
      {
        if (MODE & MAXSPI_CPOL)
          MAXSPI_CLOCK(0);
        else
          MAXSPI_DELAY(0, 0);
        MAXSPI_SHIFT( 1, 7);
        MAXSPI_LATCH( 2, 7);
        MAXSPI_SHIFT( 3, 6);
        MAXSPI_LATCH( 4, 6);
        MAXSPI_SHIFT( 5, 5);
        MAXSPI_LATCH( 6, 5);
        MAXSPI_SHIFT( 7, 4);
        MAXSPI_LATCH( 8, 4);
        MAXSPI_SHIFT( 9, 3);
        MAXSPI_LATCH(10, 3);
        MAXSPI_SHIFT(11, 2);
        MAXSPI_LATCH(12, 2);
        MAXSPI_SHIFT(13, 1);
        MAXSPI_LATCH(14, 1);
        MAXSPI_SHIFT(15, 0);
        MAXSPI_LATCH(16, 0);
      }
      else // CPHA = 0
      {
        if (MODE & MAXSPI_CPOL)
          MAXSPI_SHIFT( 0, 7);
        else
        {
          __asm__ volatile
          (
            "sbrc r23, 7"               "\n\t"
            "out  %[_MOSI_], r26"       "\n\t"
            :
            : [_MOSI_] "I" (_SFR_IO_ADDR(IOPORT_TGLREG(MOSI)))
          );
          MAXSPI_DELAY(0, 2);
        }
        MAXSPI_LATCH( 1, 7);
        MAXSPI_SHIFT( 2, 6);
        MAXSPI_LATCH( 3, 6);
        MAXSPI_SHIFT( 4, 5);
        MAXSPI_LATCH( 5, 5);
        MAXSPI_SHIFT( 6, 4);
        MAXSPI_LATCH( 7, 4);
        MAXSPI_SHIFT( 8, 3);
        MAXSPI_LATCH( 9, 3);
        MAXSPI_SHIFT(10, 2);
        MAXSPI_LATCH(11, 2);
        MAXSPI_SHIFT(12, 1);
        MAXSPI_LATCH(13, 1);
        MAXSPI_SHIFT(14, 0);
        MAXSPI_LATCH(15, 0);
        MAXSPI_CLOCK(16);
      }
      if (MODE & MAXSPI_CPOL)
        MAXSPI_CLOCK(17);
      else
        MAXSPI_DELAY(17, 0);
      return data;
    }

    static void transfer(uint8_t *buf, uint8_t len)
    {
      while (len--)
      {
        *buf = transfer(*buf);
        buf++;
      }
    }

    static void write(uint8_t data)
    {
      __asm__ volatile
      (
        "mov  r23, %[_DATA_]"       "\n\t"
        "clc"                       "\n\t"
        "sbic %[_MOSI_], %[_POSO_]" "\n\t"
        "sec"                       "\n\t"
        "ror  r23"                  "\n\t"
        "eor  r23, %[_DATA_]"       "\n\t"
        "ldi  r26, 1 << %[_POSO_]"  "\n\t"
        "ldi  r25, 1 << %[_POSC_]"  "\n\t"
        : [_DATA_] "=r" (data)
        : [_MOSI_] "I" (_SFR_IO_ADDR(IOPORT_OUTREG(MOSI)))
        , [_POSO_] "I" (IOPORT_PINPOS(MOSI))
        , [_POSC_] "I" (IOPORT_PINPOS(SCLK))
        : "r23", "r25", "r26"
      );
      if (MODE & MAXSPI_CPHA) // CPHA = 1
      {
        if (MODE & MAXSPI_CPOL)
          MAXSPI_CLOCK(0);
        else
          MAXSPI_DELAY(0, 0);
        MAXSPI_SHIFT( 1, 7);
        MAXSPI_CLOCK( 2);
        MAXSPI_SHIFT( 3, 6);
        MAXSPI_CLOCK( 4);
        MAXSPI_SHIFT( 5, 5);
        MAXSPI_CLOCK( 6);
        MAXSPI_SHIFT( 7, 4);
        MAXSPI_CLOCK( 8);
        MAXSPI_SHIFT( 9, 3);
        MAXSPI_CLOCK(10);
        MAXSPI_SHIFT(11, 2);
        MAXSPI_CLOCK(12);
        MAXSPI_SHIFT(13, 1);
        MAXSPI_CLOCK(14);
        MAXSPI_SHIFT(15, 0);
        MAXSPI_CLOCK(16);
      }
      else // CPHA = 0
      {
        if (MODE & MAXSPI_CPOL)
          MAXSPI_SHIFT( 0, 7);
        else
        {
          __asm__ volatile
          (
            "sbrc r23, 7"               "\n\t"
            "out  %[_MOSI_], r26"       "\n\t"
            :
            : [_MOSI_] "I" (_SFR_IO_ADDR(IOPORT_TGLREG(MOSI)))
          );
          MAXSPI_DELAY(0, 2);
        }
        MAXSPI_CLOCK( 1);
        MAXSPI_SHIFT( 2, 6);
        MAXSPI_CLOCK( 3);
        MAXSPI_SHIFT( 4, 5);
        MAXSPI_CLOCK( 5);
        MAXSPI_SHIFT( 6, 4);
        MAXSPI_CLOCK( 7);
        MAXSPI_SHIFT( 8, 3);
        MAXSPI_CLOCK( 9);
        MAXSPI_SHIFT(10, 2);
        MAXSPI_CLOCK(11);
        MAXSPI_SHIFT(12, 1);
        MAXSPI_CLOCK(13);
        MAXSPI_SHIFT(14, 0);
        MAXSPI_CLOCK(15);
        MAXSPI_CLOCK(16);
      }
      if (MODE & MAXSPI_CPOL)
        MAXSPI_CLOCK(17);
      else
        MAXSPI_DELAY(17, 0);
    }

    static void write(uint8_t *buf, uint8_t len)
    {
      while (len--)
        write(*buf++);
    }

    static uint8_t read(void)
    {
      uint8_t data;
      __asm__ volatile
      (
        "clr  %[_DATA_]"            "\n\t"
        "ldi  r25, 1 << %[_POSC_]"  "\n\t"
        : [_DATA_] "=r" (data)
        : [_POSC_] "I" (IOPORT_PINPOS(SCLK))
        : "r25"
      );
      if (MODE & MAXSPI_CPOL)
        MAXSPI_CLOCK(0);
      else
        MAXSPI_DELAY(0, 0);
      if (MODE & MAXSPI_CPHA) // CPHA = 1
      {
        MAXSPI_CLOCK( 1);
        MAXSPI_LATCH( 2, 7);
        MAXSPI_CLOCK( 3);
        MAXSPI_LATCH( 4, 6);
        MAXSPI_CLOCK( 5);
        MAXSPI_LATCH( 6, 5);
        MAXSPI_CLOCK( 7);
        MAXSPI_LATCH( 8, 4);
        MAXSPI_CLOCK( 9);
        MAXSPI_LATCH(10, 3);
        MAXSPI_CLOCK(11);
        MAXSPI_LATCH(12, 2);
        MAXSPI_CLOCK(13);
        MAXSPI_LATCH(14, 1);
        MAXSPI_CLOCK(15);
        MAXSPI_LATCH(16, 0);
      }
      else // CPHA = 0
      {
        MAXSPI_LATCH( 1, 7);
        MAXSPI_CLOCK( 2);
        MAXSPI_LATCH( 3, 6);
        MAXSPI_CLOCK( 4);
        MAXSPI_LATCH( 5, 5);
        MAXSPI_CLOCK( 6);
        MAXSPI_LATCH( 7, 4);
        MAXSPI_CLOCK( 8);
        MAXSPI_LATCH( 9, 3);
        MAXSPI_CLOCK(10);
        MAXSPI_LATCH(11, 2);
        MAXSPI_CLOCK(12);
        MAXSPI_LATCH(13, 1);
        MAXSPI_CLOCK(14);
        MAXSPI_LATCH(15, 0);
        MAXSPI_CLOCK(16);
      }
      if (MODE & MAXSPI_CPOL)
        MAXSPI_CLOCK(17);
      else
        MAXSPI_DELAY(17, 0);
      return data;
    }

    static void read(uint8_t *buf, uint8_t len)
    {
      while (len--)
        *buf++ = read();
    }
};

#endif

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maxspi.h - High Speed SPI Library for AVR Series

Speed: 16MHz 10.4K - 4M bps (2.6M bps)

Exsample:

#include "maxspi.h"

#define SPI_MISO IOPORT_PIN('B', 0)

#define SPI_MOSI IOPORT_PIN('B', 1)

#define SPI_SCLK IOPORT_PIN('B', 2)

#define SPI_CS IOPORT_PIN('B', 3)

#define MAXSPI MaxSpi<MAXSPI_MODE3, 1000000, SPI_MISO, SPI_MOSI, SPI_SCLK>

void setup(void)

{

IOPORT::digitalWrite(SPI_CS, HIGH);

IOPORT::pinMode(SPI_CS, OUTPUT);

MAXSPI::begin();

}

void loop(void)

{

IOPORT::digitalWrite(SPI_CS, LOW);

MAXSPI::transfer('A');

IOPORT::digitalWrite(SPI_CS, HIGH);

}

This library is free software; you can redistribute it and/or

modify it under the terms of the GNU Lesser General Public

License as published by the Free Software Foundation; either

version 2.1 of the License, or (at your option) any later version.

This library 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

Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General

Public License along with this library; if not, write to the

Free Software Foundation, Inc., 59 Temple Place, Suite 330,

Boston, MA 02111-1307 USA

#ifndef __MAXSPI_H

#define __MAXSPI_H

#include "ioport.h"

#define MAXSPI_CPOL 1

#define MAXSPI_CPHA 2

typedef enum

{

MAXSPI_MODE0 = 0, // CPOL = 0, CPHA = 0

MAXSPI_MODE1 = MAXSPI_CPHA, // CPOL = 0, CPHA = 1

MAXSPI_MODE2 = MAXSPI_CPOL | MAXSPI_CPHA, // CPOL = 1, CPHA = 1

MAXSPI_MODE3 = MAXSPI_CPOL, // CPOL = 1, CPHA = 0

} MAXSPI_MODE;

#define MAXSPI_DELAY_CYCLE 3 // cycle of delay loop

#define MAXSPI_CLOCK_CYCLE 3 // cycle of bit assembly

#define MAXSPI_CLOCK_CYCLE ((float)F_CPU / SPEED / 2)

#define MAXSPI_SWCLK_CYCLE (int)(MAXSPI_CLOCK_CYCLE + 0.5)

#define MAXSPI_DELAY(n, c) \

do \

{ \

int cycle = 0; \

float error = MAXSPI_CLOCK_CYCLE - MAXSPI_SWCLK_CYCLE; \

float round = (error < 0 ? -0.5 : 0.5); \

error -= (int)error; \

if (((int)(error * (n) + round) ^ (int)(error * ((n) + 1) + round)) & 1) \

cycle += (error < 0 ? -1 : 1); \

if ((cycle += MAXSPI_SWCLK_CYCLE - (c)) > 0) \

{ \

if (cycle / MAXSPI_DELAY_CYCLE) \

__asm__ volatile \

( \

"ldi r22, %[_COUNT_]" "\n\t" \

"1: dec r22" "\n\t" \

"brne 1b" "\n\t" \

: \

: [_COUNT_] "M" (cycle / MAXSPI_DELAY_CYCLE) \

: "r22" \

); \

if ((cycle % MAXSPI_DELAY_CYCLE) > 0) \

__asm__ volatile ("nop"); \

if ((cycle % MAXSPI_DELAY_CYCLE) > 1) \

__asm__ volatile ("nop"); \

} \

while (0)

#define MAXSPI_SHIFT(no, bit) \

do \

{ \

__asm__ volatile \

( \

"out %[_SCLK_], r25" "\n\t" \

"sbrc r23, %[_BPOS_]" "\n\t" \

"out %[_MOSI_], r26" "\n\t" \

: \

: [_SCLK_] "I" (_SFR_IO_ADDR(IOPORT_TGLREG(SCLK))) \

, [_MOSI_] "I" (_SFR_IO_ADDR(IOPORT_TGLREG(MOSI))) \

, [_BPOS_] "I" (bit) \

); \

MAXSPI_DELAY(no, MAXSPI_CLOCK_CYCLE); \

} \

while (0)

#define MAXSPI_LATCH(no, bit) \

do \

{ \

__asm__ volatile \

( \

"out %[_SCLK_], r25" "\n\t" \

"sbic %[_MISO_], %[_POSI_]" "\n\t" \

"ori %[_DATA_], 1 << %[_BPOS_]" "\n\t" \

: [_DATA_] "=r" (data) \

: [_SCLK_] "I" (_SFR_IO_ADDR(IOPORT_TGLREG(SCLK))) \

, [_MISO_] "I" (_SFR_IO_ADDR(IOPORT_INREG(MISO))) \

, [_POSI_] "I" (IOPORT_PINPOS(MISO)) \

, [_BPOS_] "I" (bit) \

); \

MAXSPI_DELAY(no, MAXSPI_CLOCK_CYCLE); \

} \

while (0)

#define MAXSPI_CLOCK(no) \

do \

{ \

__asm__ volatile \

( \

"out %[_SCLK_], r25" "\n\t" \

: \

: [_SCLK_] "I" (_SFR_IO_ADDR(IOPORT_TGLREG(SCLK))) \

); \

MAXSPI_DELAY(no, 1); \

} \

while (0)

template<MAXSPI_MODE MODE, uint32_t SPEED, uint8_t MISO, uint8_t MOSI, uint8_t SCLK>

class MaxSpi

{

public:

static void begin(void)

{

IOPORT::digitalWrite(SCLK, MODE & MAXSPI_CPOL ? HIGH : LOW);

IOPORT::pinMode(SCLK, OUTPUT);

IOPORT::pinMode(MOSI, OUTPUT);

IOPORT::pinMode(MISO, INPUT );

}

static void end(void)

{

IOPORT::pinMode(SCLK, INPUT);

IOPORT::pinMode(MOSI, INPUT);

}

static uint8_t transfer(uint8_t data)

{

__asm__ volatile

(

"mov r23, %[_DATA_]" "\n\t"

"clc" "\n\t"

"sbic %[_MOSI_], %[_POSO_]" "\n\t"

"sec" "\n\t"

"ror r23" "\n\t"

"eor r23, %[_DATA_]" "\n\t"

"clr %[_DATA_]" "\n\t"

"ldi r26, 1 << %[_POSO_]" "\n\t"

"ldi r25, 1 << %[_POSC_]" "\n\t"

: [_DATA_] "=r" (data)

: [_MOSI_] "I" (_SFR_IO_ADDR(IOPORT_OUTREG(MOSI)))

, [_POSO_] "I" (IOPORT_PINPOS(MOSI))

, [_POSC_] "I" (IOPORT_PINPOS(SCLK))

: "r23", "r25", "r26"

);

if (MODE & MAXSPI_CPHA) // CPHA = 1

{

if (MODE & MAXSPI_CPOL)

MAXSPI_CLOCK(0);

else

MAXSPI_DELAY(0, 0);

MAXSPI_SHIFT( 1, 7);

MAXSPI_LATCH( 2, 7);

MAXSPI_SHIFT( 3, 6);

MAXSPI_LATCH( 4, 6);

MAXSPI_SHIFT( 5, 5);

MAXSPI_LATCH( 6, 5);

MAXSPI_SHIFT( 7, 4);

MAXSPI_LATCH( 8, 4);

MAXSPI_SHIFT( 9, 3);

MAXSPI_LATCH(10, 3);

MAXSPI_SHIFT(11, 2);

MAXSPI_LATCH(12, 2);

MAXSPI_SHIFT(13, 1);

MAXSPI_LATCH(14, 1);

MAXSPI_SHIFT(15, 0);

MAXSPI_LATCH(16, 0);

}

else // CPHA = 0

{

if (MODE & MAXSPI_CPOL)

MAXSPI_SHIFT( 0, 7);

else

{

__asm__ volatile

(

"sbrc r23, 7" "\n\t"

"out %[_MOSI_], r26" "\n\t"

: [_MOSI_] "I" (_SFR_IO_ADDR(IOPORT_TGLREG(MOSI)))

);

MAXSPI_DELAY(0, 2);

}

MAXSPI_LATCH( 1, 7);

MAXSPI_SHIFT( 2, 6);

MAXSPI_LATCH( 3, 6);

MAXSPI_SHIFT( 4, 5);

MAXSPI_LATCH( 5, 5);

MAXSPI_SHIFT( 6, 4);

MAXSPI_LATCH( 7, 4);

MAXSPI_SHIFT( 8, 3);

MAXSPI_LATCH( 9, 3);

MAXSPI_SHIFT(10, 2);

MAXSPI_LATCH(11, 2);

MAXSPI_SHIFT(12, 1);

MAXSPI_LATCH(13, 1);

MAXSPI_SHIFT(14, 0);

MAXSPI_LATCH(15, 0);

MAXSPI_CLOCK(16);

}

if (MODE & MAXSPI_CPOL)

MAXSPI_CLOCK(17);

else

MAXSPI_DELAY(17, 0);

return data;

}

static void transfer(uint8_t *buf, uint8_t len)

{

while (len--)

{

*buf = transfer(*buf);

buf++;

}

static void write(uint8_t data)

{

__asm__ volatile

(

"mov r23, %[_DATA_]" "\n\t"

"clc" "\n\t"

"sbic %[_MOSI_], %[_POSO_]" "\n\t"

"sec" "\n\t"

"ror r23" "\n\t"

"eor r23, %[_DATA_]" "\n\t"

"ldi r26, 1 << %[_POSO_]" "\n\t"

"ldi r25, 1 << %[_POSC_]" "\n\t"

: [_DATA_] "=r" (data)

: [_MOSI_] "I" (_SFR_IO_ADDR(IOPORT_OUTREG(MOSI)))

, [_POSO_] "I" (IOPORT_PINPOS(MOSI))

, [_POSC_] "I" (IOPORT_PINPOS(SCLK))

: "r23", "r25", "r26"

);

if (MODE & MAXSPI_CPHA) // CPHA = 1

{

if (MODE & MAXSPI_CPOL)

MAXSPI_CLOCK(0);

else

MAXSPI_DELAY(0, 0);

MAXSPI_SHIFT( 1, 7);

MAXSPI_CLOCK( 2);

MAXSPI_SHIFT( 3, 6);

MAXSPI_CLOCK( 4);

MAXSPI_SHIFT( 5, 5);

MAXSPI_CLOCK( 6);

MAXSPI_SHIFT( 7, 4);

MAXSPI_CLOCK( 8);

MAXSPI_SHIFT( 9, 3);

MAXSPI_CLOCK(10);

MAXSPI_SHIFT(11, 2);

MAXSPI_CLOCK(12);

MAXSPI_SHIFT(13, 1);

MAXSPI_CLOCK(14);

MAXSPI_SHIFT(15, 0);

MAXSPI_CLOCK(16);

}

else // CPHA = 0

{

if (MODE & MAXSPI_CPOL)

MAXSPI_SHIFT( 0, 7);

else

{

__asm__ volatile

(

"sbrc r23, 7" "\n\t"

"out %[_MOSI_], r26" "\n\t"

: [_MOSI_] "I" (_SFR_IO_ADDR(IOPORT_TGLREG(MOSI)))

);

MAXSPI_DELAY(0, 2);

}

MAXSPI_CLOCK( 1);

MAXSPI_SHIFT( 2, 6);

MAXSPI_CLOCK( 3);

MAXSPI_SHIFT( 4, 5);

MAXSPI_CLOCK( 5);

MAXSPI_SHIFT( 6, 4);

MAXSPI_CLOCK( 7);

MAXSPI_SHIFT( 8, 3);

MAXSPI_CLOCK( 9);

MAXSPI_SHIFT(10, 2);

MAXSPI_CLOCK(11);

MAXSPI_SHIFT(12, 1);

MAXSPI_CLOCK(13);

MAXSPI_SHIFT(14, 0);

MAXSPI_CLOCK(15);

MAXSPI_CLOCK(16);

}

if (MODE & MAXSPI_CPOL)

MAXSPI_CLOCK(17);

else

MAXSPI_DELAY(17, 0);

}

static void write(uint8_t *buf, uint8_t len)

{

while (len--)

write(*buf++);

}

static uint8_t read(void)

{

uint8_t data;

__asm__ volatile

(

"clr %[_DATA_]" "\n\t"

"ldi r25, 1 << %[_POSC_]" "\n\t"

: [_DATA_] "=r" (data)

: [_POSC_] "I" (IOPORT_PINPOS(SCLK))

: "r25"

);

if (MODE & MAXSPI_CPOL)

MAXSPI_CLOCK(0);

else

MAXSPI_DELAY(0, 0);

if (MODE & MAXSPI_CPHA) // CPHA = 1

{

MAXSPI_CLOCK( 1);

MAXSPI_LATCH( 2, 7);

MAXSPI_CLOCK( 3);

MAXSPI_LATCH( 4, 6);

MAXSPI_CLOCK( 5);

MAXSPI_LATCH( 6, 5);

MAXSPI_CLOCK( 7);

MAXSPI_LATCH( 8, 4);

MAXSPI_CLOCK( 9);

MAXSPI_LATCH(10, 3);

MAXSPI_CLOCK(11);

MAXSPI_LATCH(12, 2);

MAXSPI_CLOCK(13);

MAXSPI_LATCH(14, 1);

MAXSPI_CLOCK(15);

MAXSPI_LATCH(16, 0);

}

else // CPHA = 0

{

MAXSPI_LATCH( 1, 7);

MAXSPI_CLOCK( 2);

MAXSPI_LATCH( 3, 6);

MAXSPI_CLOCK( 4);

MAXSPI_LATCH( 5, 5);

MAXSPI_CLOCK( 6);

MAXSPI_LATCH( 7, 4);

MAXSPI_CLOCK( 8);

MAXSPI_LATCH( 9, 3);

MAXSPI_CLOCK(10);

MAXSPI_LATCH(11, 2);

MAXSPI_CLOCK(12);

MAXSPI_LATCH(13, 1);

MAXSPI_CLOCK(14);

MAXSPI_LATCH(15, 0);

MAXSPI_CLOCK(16);

}

if (MODE & MAXSPI_CPOL)

MAXSPI_CLOCK(17);

else

MAXSPI_DELAY(17, 0);

return data;

}

static void read(uint8_t *buf, uint8_t len)

{

while (len--)

*buf++ = read();

}

};

#endif

【参照ライブラリ】
AVR用高速GPIOライブラリ

月: 2020年7月

ソフトウェア処理の限界に挑む。AVR用高速SPIライブラリを作ってみた。