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SPI.cpp
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SPI.cpp
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/*
* SPI Master library for Arduino Zero.
* Copyright (c) 2015 Arduino LLC
*
* 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "SPI.h"
#include <Arduino.h>
#include <wiring_private.h>
#include <assert.h>
#define SPI_IMODE_NONE 0
#define SPI_IMODE_EXTINT 1
#define SPI_IMODE_GLOBAL 2
//const SPISettings DEFAULT_SPI_SETTINGS = SPISettings();
static inline SercomDataOrder getBitOrder(SPISettings& settings) {
return (settings.getBitOrder() == MSBFIRST ? MSB_FIRST : LSB_FIRST);
}
static inline SercomSpiClockMode getDataMode(SPISettings& settings) {
switch (settings.getDataMode())
{
case SPI_MODE0:
return SERCOM_SPI_MODE_0; break;
case SPI_MODE1:
return SERCOM_SPI_MODE_1; break;
case SPI_MODE2:
return SERCOM_SPI_MODE_2; break;
case SPI_MODE3:
return SERCOM_SPI_MODE_3; break;
default:
return SERCOM_SPI_MODE_0; break;
}
}
SPIClassSAMD::SPIClassSAMD(SERCOM *p_sercom, uint8_t uc_pinMISO, uint8_t uc_pinSCK, uint8_t uc_pinMOSI, SercomSpiTXPad PadTx, SercomRXPad PadRx)
: settings(0, MSBFIRST, SPI_MODE0)
{
initialized = false;
assert(p_sercom != NULL);
_p_sercom = p_sercom;
// pins
_uc_pinMiso = uc_pinMISO;
_uc_pinSCK = uc_pinSCK;
_uc_pinMosi = uc_pinMOSI;
// SERCOM pads
_padTx=PadTx;
_padRx=PadRx;
}
void SPIClassSAMD::begin()
{
init();
// PIO init
pinPeripheral(_uc_pinMiso, g_APinDescription[_uc_pinMiso].ulPinType);
pinPeripheral(_uc_pinSCK, g_APinDescription[_uc_pinSCK].ulPinType);
pinPeripheral(_uc_pinMosi, g_APinDescription[_uc_pinMosi].ulPinType);
config(DEFAULT_SPI_SETTINGS);
}
void SPIClassSAMD::init()
{
if (initialized)
return;
interruptMode = SPI_IMODE_NONE;
interruptSave = 0;
interruptMask = 0;
initialized = true;
}
void SPIClassSAMD::config(SPISettings settings)
{
if (this->settings != settings) {
this->settings = settings;
_p_sercom->disableSPI();
uint32_t clock_freq = settings.getClockFreq();
if (clock_freq > SERCOM_FREQ_REF/SPI_MIN_CLOCK_DIVIDER) {
clock_freq = SERCOM_FREQ_REF/SPI_MIN_CLOCK_DIVIDER;
}
_p_sercom->initSPI(_padTx, _padRx, SPI_CHAR_SIZE_8_BITS, getBitOrder(settings));
_p_sercom->initSPIClock(getDataMode(settings), clock_freq);
_p_sercom->enableSPI();
}
}
void SPIClassSAMD::end()
{
_p_sercom->resetSPI();
initialized = false;
}
#ifndef interruptsStatus
#define interruptsStatus() __interruptsStatus()
static inline unsigned char __interruptsStatus(void) __attribute__((always_inline, unused));
static inline unsigned char __interruptsStatus(void)
{
// See http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0497a/CHDBIBGJ.html
return (__get_PRIMASK() ? 0 : 1);
}
#endif
void SPIClassSAMD::usingInterrupt(int interruptNumber)
{
if ((interruptNumber == NOT_AN_INTERRUPT) || (interruptNumber == EXTERNAL_INT_NMI))
return;
uint8_t irestore = interruptsStatus();
noInterrupts();
if (interruptNumber >= EXTERNAL_NUM_INTERRUPTS)
interruptMode = SPI_IMODE_GLOBAL;
else
{
interruptMode |= SPI_IMODE_EXTINT;
interruptMask |= (1 << g_APinDescription[interruptNumber].ulExtInt);
}
if (irestore)
interrupts();
}
void SPIClassSAMD::notUsingInterrupt(int interruptNumber)
{
if ((interruptNumber == NOT_AN_INTERRUPT) || (interruptNumber == EXTERNAL_INT_NMI))
return;
if (interruptMode & SPI_IMODE_GLOBAL)
return; // can't go back, as there is no reference count
uint8_t irestore = interruptsStatus();
noInterrupts();
interruptMask &= ~(1 << g_APinDescription[interruptNumber].ulExtInt);
if (interruptMask == 0)
interruptMode = SPI_IMODE_NONE;
if (irestore)
interrupts();
}
void SPIClassSAMD::beginTransaction(SPISettings settings)
{
if (interruptMode != SPI_IMODE_NONE)
{
if (interruptMode & SPI_IMODE_GLOBAL)
{
interruptSave = interruptsStatus();
noInterrupts();
}
else if (interruptMode & SPI_IMODE_EXTINT)
EIC->INTENCLR.reg = EIC_INTENCLR_EXTINT(interruptMask);
}
config(settings);
}
void SPIClassSAMD::endTransaction(void)
{
if (interruptMode != SPI_IMODE_NONE)
{
if (interruptMode & SPI_IMODE_GLOBAL)
{
if (interruptSave)
interrupts();
}
else if (interruptMode & SPI_IMODE_EXTINT)
EIC->INTENSET.reg = EIC_INTENSET_EXTINT(interruptMask);
}
}
void SPIClassSAMD::setBitOrder(BitOrder order)
{
if (order == LSBFIRST) {
_p_sercom->setDataOrderSPI(LSB_FIRST);
} else {
_p_sercom->setDataOrderSPI(MSB_FIRST);
}
}
void SPIClassSAMD::setDataMode(uint8_t mode)
{
switch (mode)
{
case SPI_MODE0:
_p_sercom->setClockModeSPI(SERCOM_SPI_MODE_0);
break;
case SPI_MODE1:
_p_sercom->setClockModeSPI(SERCOM_SPI_MODE_1);
break;
case SPI_MODE2:
_p_sercom->setClockModeSPI(SERCOM_SPI_MODE_2);
break;
case SPI_MODE3:
_p_sercom->setClockModeSPI(SERCOM_SPI_MODE_3);
break;
default:
break;
}
}
void SPIClassSAMD::setClockDivider(uint8_t div)
{
if (div < SPI_MIN_CLOCK_DIVIDER) {
_p_sercom->setBaudrateSPI(SPI_MIN_CLOCK_DIVIDER);
} else {
_p_sercom->setBaudrateSPI(div);
}
}
byte SPIClassSAMD::transfer(uint8_t data)
{
return _p_sercom->transferDataSPI(data);
}
uint16_t SPIClassSAMD::transfer16(uint16_t data) {
union { uint16_t val; struct { uint8_t lsb; uint8_t msb; }; } t;
t.val = data;
if (_p_sercom->getDataOrderSPI() == LSB_FIRST) {
t.lsb = transfer(t.lsb);
t.msb = transfer(t.msb);
} else {
t.msb = transfer(t.msb);
t.lsb = transfer(t.lsb);
}
return t.val;
}
void SPIClassSAMD::transfer(void *buf, size_t count)
{
uint8_t *buffer = reinterpret_cast<uint8_t *>(buf);
for (size_t i=0; i<count; i++) {
*buffer = transfer(*buffer);
buffer++;
}
}
void SPIClassSAMD::attachInterrupt() {
// Should be enableInterrupt()
}
void SPIClassSAMD::detachInterrupt() {
// Should be disableInterrupt()
}
#if SPI_INTERFACES_COUNT > 0
/* In case new variant doesn't define these macros,
* we put here the ones for Arduino Zero.
*
* These values should be different on some variants!
*
* The SPI PAD values can be found in cores/arduino/SERCOM.h:
* - SercomSpiTXPad
* - SercomRXPad
*/
#ifndef PERIPH_SPI
#define PERIPH_SPI sercom4
#define PAD_SPI_TX SPI_PAD_2_SCK_3
#define PAD_SPI_RX SERCOM_RX_PAD_0
#endif // PERIPH_SPI
SPIClassSAMD SPI (&PERIPH_SPI, PIN_SPI_MISO, PIN_SPI_SCK, PIN_SPI_MOSI, PAD_SPI_TX, PAD_SPI_RX);
#endif
#if SPI_INTERFACES_COUNT > 1
SPIClassSAMD SPI1(&PERIPH_SPI1, PIN_SPI1_MISO, PIN_SPI1_SCK, PIN_SPI1_MOSI, PAD_SPI1_TX, PAD_SPI1_RX);
#endif
#if SPI_INTERFACES_COUNT > 2
SPIClassSAMD SPI2(&PERIPH_SPI2, PIN_SPI2_MISO, PIN_SPI2_SCK, PIN_SPI2_MOSI, PAD_SPI2_TX, PAD_SPI2_RX);
#endif
#if SPI_INTERFACES_COUNT > 3
SPIClassSAMD SPI3(&PERIPH_SPI3, PIN_SPI3_MISO, PIN_SPI3_SCK, PIN_SPI3_MOSI, PAD_SPI3_TX, PAD_SPI3_RX);
#endif
#if SPI_INTERFACES_COUNT > 4
SPIClassSAMD SPI4(&PERIPH_SPI4, PIN_SPI4_MISO, PIN_SPI4_SCK, PIN_SPI4_MOSI, PAD_SPI4_TX, PAD_SPI4_RX);
#endif
#if SPI_INTERFACES_COUNT > 5
SPIClassSAMD SPI5(&PERIPH_SPI5, PIN_SPI5_MISO, PIN_SPI5_SCK, PIN_SPI5_MOSI, PAD_SPI5_TX, PAD_SPI5_RX);
#endif