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Arduino/hardware/arduino/sam/libraries/SPI/SPI.cpp
2012-08-24 15:23:50 +02:00

129 lines
3.7 KiB
C++

/*
* Copyright (c) 2010 by Cristian Maglie <c.maglie@bug.st>
* SPI Master library for arduino.
*
* This file is free software; you can redistribute it and/or modify
* it under the terms of either the GNU General Public License version 2
* or the GNU Lesser General Public License version 2.1, both as
* published by the Free Software Foundation.
*/
#include "SPI.h"
SPIClass::SPIClass(Spi *_spi, uint32_t _id, void(*_initCb)(void)) :
spi(_spi), id(_id), initCb(_initCb)
{
initCb();
SPI_Configure(spi, id, SPI_MR_MSTR | SPI_MR_PS | SPI_MR_MODFDIS);
SPI_Enable(spi);
}
void SPIClass::begin() {
// NPCS control is left to the user
// Default speed set to 4Mhz
setClockDivider(BOARD_SPI_DEFAULT_SS, 21);
setDataMode(BOARD_SPI_DEFAULT_SS, SPI_MODE0);
setBitOrder(BOARD_SPI_DEFAULT_SS, MSBFIRST);
}
void SPIClass::begin(uint8_t _pin) {
uint32_t spiPin = BOARD_PIN_TO_SPI_PIN(_pin);
PIO_Configure(
g_APinDescription[spiPin].pPort,
g_APinDescription[spiPin].ulPinType,
g_APinDescription[spiPin].ulPin,
g_APinDescription[spiPin].ulPinConfiguration);
// Default speed set to 500Khz
setClockDivider(_pin, 168);
setDataMode(_pin, SPI_MODE0);
setBitOrder(_pin, MSBFIRST);
}
void SPIClass::end(uint8_t _pin) {
uint32_t spiPin = BOARD_PIN_TO_SPI_PIN(_pin);
// Setting the pin as INPUT will disconnect it from SPI peripheral
pinMode(spiPin, INPUT);
}
void SPIClass::end() {
SPI_Disable(spi);
}
void SPIClass::setBitOrder(uint8_t _pin, BitOrder _bitOrder) {
uint32_t ch = BOARD_PIN_TO_SPI_CHANNEL(_pin);
bitOrder[ch] = _bitOrder;
}
void SPIClass::setDataMode(uint8_t _pin, uint8_t _mode) {
uint32_t ch = BOARD_PIN_TO_SPI_CHANNEL(_pin);
mode[ch] = _mode | SPI_CSR_CSAAT;
// SPI_CSR_DLYBCT(1) keeps CS enabled for 32 MCLK after a completed
// transfer. Some device needs that for working properly.
SPI_ConfigureNPCS(spi, ch, mode[ch] | SPI_CSR_SCBR(divider[ch]) | SPI_CSR_DLYBCT(1));
}
void SPIClass::setClockDivider(uint8_t _pin, uint8_t _divider) {
uint32_t ch = BOARD_PIN_TO_SPI_CHANNEL(_pin);
divider[ch] = _divider;
// SPI_CSR_DLYBCT(1) keeps CS enabled for 32 MCLK after a completed
// transfer. Some device needs that for working properly.
SPI_ConfigureNPCS(spi, ch, mode[ch] | SPI_CSR_SCBR(divider[ch]) | SPI_CSR_DLYBCT(1));
}
byte SPIClass::transfer(byte _pin, uint8_t _data, SPITransferMode _mode) {
uint32_t ch = BOARD_PIN_TO_SPI_CHANNEL(_pin);
// Reverse bit order
if (bitOrder[ch] == LSBFIRST)
_data = __REV(__RBIT(_data));
uint32_t d = _data | SPI_PCS(ch);
if (_mode == SPI_LAST)
d |= SPI_TDR_LASTXFER;
// SPI_Write(spi, _channel, _data);
while ((spi->SPI_SR & SPI_SR_TDRE) == 0)
;
spi->SPI_TDR = d;
// return SPI_Read(spi);
while ((spi->SPI_SR & SPI_SR_RDRF) == 0)
;
d = spi->SPI_RDR;
// Reverse bit order
if (bitOrder[ch] == LSBFIRST)
d = __REV(__RBIT(d));
return d & 0xFF;
}
void SPIClass::attachInterrupt(void) {
// Should be enableInterrupt()
}
void SPIClass::detachInterrupt(void) {
// Should be disableInterrupt()
}
#if SPI_INTERFACES_COUNT > 0
static void SPI_0_Init(void) {
PIO_Configure(
g_APinDescription[PIN_SPI_MOSI].pPort,
g_APinDescription[PIN_SPI_MOSI].ulPinType,
g_APinDescription[PIN_SPI_MOSI].ulPin,
g_APinDescription[PIN_SPI_MOSI].ulPinConfiguration);
PIO_Configure(
g_APinDescription[PIN_SPI_MISO].pPort,
g_APinDescription[PIN_SPI_MISO].ulPinType,
g_APinDescription[PIN_SPI_MISO].ulPin,
g_APinDescription[PIN_SPI_MISO].ulPinConfiguration);
PIO_Configure(
g_APinDescription[PIN_SPI_SCK].pPort,
g_APinDescription[PIN_SPI_SCK].ulPinType,
g_APinDescription[PIN_SPI_SCK].ulPin,
g_APinDescription[PIN_SPI_SCK].ulPinConfiguration);
}
SPIClass SPI(SPI_INTERFACE, SPI_INTERFACE_ID, SPI_0_Init);
#endif