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。
Raspberry Pi 5のRP1-Chipを使い倒す(GPIO)
【仕様】
・マスターモードのみ
・最大通信速度はwrite()のみ5MHz、他は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
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 = 1000000);
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】
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#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！ */ int CS[] = { 8, -7 }; SPI_GPIO spi(rp1, 11, 10, 9, CS, sizeof(CS) / sizeof(CS[0])); /* 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:1000000ns */ /* 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】
2025-05-13
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】
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/* 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 <limits.h> #include "rp1-gpio.h" class SPI_GPIO { public: 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 cssize = 0) : _gpio(&gpio), _sclk(sclk), _mosi(mosi), _miso(miso) { setupCS(cspins, cssize); } virtual ~SPI_GPIO(void) { } void begin(MODE mode, long speed, int databit = 8, BITORDER bitorder = MSBFIRST, long delay = 1000000) { _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) { select(cs); int rv = write(buf, len); deselect(cs); return rv; } int read(int cs, void *buf, size_t len) { select(cs); int rv = read(buf, len); deselect(cs); return rv; } int writeAndRead(int cs, const void *wbuf, size_t wlen, void *rbuf, size_t rlen) { select(cs); int rv = writeAndRead(wbuf, wlen, rbuf, rlen); deselect(cs); return rv; } void transfer(int cs, void *buf, size_t len) { select(cs); transfer(buf, len); deselect(cs); } uint32_t transfer(int cs, uint32_t data) { select(cs); data = transfer(data); deselect(cs); return data; } void select(int cs = -1) { select0(cs, true); } void deselect(int cs = -1) { select0(cs, false); } int write(const void *buf, size_t len) { if (_dbit < 8) { const uint8_t *p = (const uint8_t *)buf; for (size_t i = 0; i < len; ++i) transfer0(p[i], false); } else if (_dbit < 16) { const uint16_t *p = (const uint16_t *)buf; for (size_t i = 0; i < len; ++i) transfer0(p[i], false); } else { const uint32_t *p = (const uint32_t *)buf; for (size_t i = 0; i < len; ++i) transfer0(p[i], false); } return len; } int read(void *buf, size_t len) { if (_dbit < 8) { uint8_t *p = (uint8_t *)buf; for (size_t i = 0; i < len; ++i) p[i] = transfer0(0xFFFFFFFF); } else if (_dbit < 16) { uint16_t *p = (uint16_t *)buf; for (size_t i = 0; i < len; ++i) p[i] = transfer0(0xFFFFFFFF); } else { uint32_t *p = (uint32_t *)buf; for (size_t i = 0; i < len; ++i) p[i] = transfer0(0xFFFFFFFF); } return len; } int writeAndRead(const void *wbuf, size_t wlen, void *rbuf, size_t rlen) { int rv = 0; if (wbuf && wlen) write(wbuf, wlen); if (rbuf && rlen) rv = read(rbuf, rlen); return rv; } void transfer(void *buf, size_t len) { if (_dbit < 8) { uint8_t *p = (uint8_t *)buf; for (size_t i = 0; i < len; ++i) p[i] = transfer0(p[i]); } else if (_dbit < 16) { uint16_t *p = (uint16_t *)buf; for (size_t i = 0; i < len; ++i) p[i] = transfer0(p[i]); } else { uint32_t *p = (uint32_t *)buf; for (size_t i = 0; i < len; ++i) p[i] = transfer0(p[i]); } } uint32_t transfer(uint32_t data) { return transfer0(data); } 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; int _cs[32]; 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 setupCS(const int *pins, size_t size) { for (size_t i = 0; i < sizeof(_cs) / sizeof(_cs[0]); ++i) _cs[i] = pins && (i < size) ? pins[i] : INT_MIN; } void outputCS(int pin, bool enable) { if (pin != INT_MIN) { 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 < sizeof(_cs) / sizeof(_cs[0]); ++i) { int cs = _cs[i]; if (cs != INT_MIN) _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); } void select0(int cs, bool enable) { if (!enable) { delay(_clock); clock(_mode & CPOL ? HIGH : LOW); delay(_delay); } if ((cs >= 0) && (cs < (int)(sizeof(_cs) / sizeof(_cs[0])))) outputCS(_cs[cs], enable); if (enable) { delay(_delay); clock(LOW); } } uint32_t transfer0(uint32_t b, bool read = true) { input(_sclk); /* good luck charm */ if ((_mode == MODE0) || (_mode == MODE3)) { delay(_clock); 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); data(b & (_bord ? _dmsb : 1)); clock(HIGH); delay(_clock); if (_bord) b = (b << 1) | (read ? input(_miso) : 0); else b = (b >> 1) | (read ? input(_miso) << _dbit : 0); clock(LOW); } } return b & (_dmsb | (_dmsb - 1)); } }; 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 = 1000000) : _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 cssize = 0) : SPI_GPIO(gpio, sclk, mosi, miso, cspins, cssize) { } 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); } }; |