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88 lines
2.0 KiB
C++
88 lines
2.0 KiB
C++
/*
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* Copyright (c) 2010 by Cristian Maglie <c.maglie@bug.st>
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* SPI Master library for arduino.
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*
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* This file is free software; you can redistribute it and/or modify
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* it under the terms of either the GNU General Public License version 2
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* or the GNU Lesser General Public License version 2.1, both as
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* published by the Free Software Foundation.
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*/
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#include "pins_arduino.h"
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#include "SPI.h"
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SPIClass SPI;
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SPIClass::SPIClass()
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{
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// Set direction register for SCK and MOSI pin.
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// MISO pin automatically overrides to INPUT.
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// When the SS pin is set as OUTPUT, it can be used as
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// a general purpose output port (it doesn't influence
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// SPI operations).
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pinMode(SCK, OUTPUT);
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pinMode(MOSI, OUTPUT);
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pinMode(SS, OUTPUT);
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digitalWrite(SCK, LOW);
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digitalWrite(MOSI, LOW);
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digitalWrite(SS, LOW);
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SPCR = _BV(SPE) | _BV(MSTR);
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// Warning: if the SS pin ever becomes a LOW INPUT then SPI
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// automatically switches to Slave, so the data direction of
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// the SS pin MUST be kept as OUTPUT.
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SPCR = _BV(SPE) | _BV(MSTR);
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}
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void SPIClass::setDataOrder(SPIDataOrder _d)
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{
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if (_d == SPI_DataOrder_LSB)
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SPCR |= _BV(DORD); // LSB
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else
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SPCR &= ~_BV(DORD); // MSB
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}
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void SPIClass::setSPIMode(SPIMode _d)
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{
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switch (_d) {
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case SPI_Mode_SampleRising:
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SPCR &= ~(_BV(CPOL) | _BV(CPHA));
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break;
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case SPI_Mode_SetupRising:
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SPCR &= ~_BV(CPOL);
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SPCR |= _BV(CPHA);
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break;
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case SPI_Mode_SampleFalling:
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SPCR &= ~_BV(CPHA);
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SPCR |= _BV(CPOL);
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break;
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case SPI_Mode_SetupFalling:
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SPCR |= _BV(CPOL) | _BV(CPHA);
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break;
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}
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}
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void SPIClass::setClockDivider(SPIClockDivider _d)
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{
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switch (_d) {
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case SPI_ClkDiv_4:
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SPCR &= ~(_BV(SPR1) | _BV(SPR0));
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break;
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case SPI_ClkDiv_16:
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SPCR &= ~_BV(SPR1);
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SPCR |= _BV(SPR0);
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break;
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case SPI_ClkDiv_64:
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SPCR |= _BV(SPR1);
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SPCR &= ~_BV(SPR0);
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break;
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case SPI_ClkDiv_128:
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SPCR |= _BV(SPR1) | _BV(SPR0);
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break;
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}
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}
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