SPI.cpp

/* 
 SPI.cpp - SPI library for esp8266

 Copyright (c) 2015 Hristo Gochkov. All rights reserved.
 This file is part of the esp8266 core for Arduino environment.
 
 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"

SPIClass::SPIClass(uint8_t spi_bus)
    :_spi_num(spi_bus)
    ,_spi(NULL)
    ,_use_hw_ss(false)
    ,_sck(-1)
    ,_miso(-1)
    ,_mosi(-1)
    ,_ss(-1)
    ,_div(0)
    ,_freq(1000000)
{}

void SPIClass::begin(int8_t sck, int8_t miso, int8_t mosi, int8_t ss)
{
    if(_spi) {
        return;
    }

    if(!_div) {
        _div = spiFrequencyToClockDiv(_freq);
    }

    _spi = spiStartBus(_spi_num, _div, SPI_MODE0, SPI_MSBFIRST);
    if(!_spi) {
        return;
    }

    _sck = sck;
    _miso = miso;
    _mosi = mosi;
    _ss = ss;

    spiAttachSCK(_spi, _sck);
    spiAttachMISO(_spi, _miso);
    spiAttachMOSI(_spi, _mosi);

}

void SPIClass::end()
{
    if(!_spi) {
        return;
    }
    spiDetachSCK(_spi, _sck);
    spiDetachMISO(_spi, _miso);
    spiDetachMOSI(_spi, _mosi);
    setHwCs(false);
    spiStopBus(_spi);
    _spi = NULL;
}

void SPIClass::setHwCs(bool use)
{
    if(use && !_use_hw_ss) {
        spiAttachSS(_spi, 0, _ss);
        spiSSEnable(_spi);
    } else if(_use_hw_ss) {
        spiSSDisable(_spi);
        spiDetachSS(_spi, _ss);
    }
    _use_hw_ss = use;
}

void SPIClass::beginTransaction(SPISettings settings)
{
    spiWaitReady(_spi);
    setFrequency(settings._clock);
    setBitOrder(settings._bitOrder);
    setDataMode(settings._dataMode);
}

void SPIClass::endTransaction() {}

void SPIClass::setFrequency(uint32_t freq)
{
    //check if last freq changed
    uint32_t cdiv = spiGetClockDiv(_spi);
    if(_freq != freq || _div != cdiv) {
        _freq = freq;
        _div = spiFrequencyToClockDiv(_freq);
        spiSetClockDiv(_spi, _div);
    }
}

void SPIClass::setClockDivider(uint32_t clockDiv)
{
    _div = clockDiv;
    spiSetClockDiv(_spi, _div);
}

void SPIClass::setDataMode(uint8_t dataMode)
{
    spiSetDataMode(_spi, dataMode);
}

void SPIClass::setBitOrder(uint8_t bitOrder)
{
    spiSetBitOrder(_spi, bitOrder);
}

void SPIClass::write(uint8_t data)
{
    spiWriteByte(_spi, data);
}

uint8_t SPIClass::transfer(uint8_t data)
{
    spiWriteByte(_spi, data);
    return spiReadByte(_spi);
}

void SPIClass::write16(uint16_t data)
{
    spiWriteWord(_spi, data);
}

uint16_t SPIClass::transfer16(uint16_t data)
{
    spiWriteWord(_spi, data);
    return spiReadWord(_spi);
}

void SPIClass::write32(uint32_t data)
{
    spiWriteLong(_spi, data);
}

uint32_t SPIClass::transfer32(uint32_t data)
{
    spiWriteLong(_spi, data);
    return spiReadLong(_spi);
}

void SPIClass::transferBits(uint32_t data, uint32_t * out, uint8_t bits)
{
    spiTransferBits(_spi, data, out, bits);
}

/**
 * Note:
 *  data need to be aligned to 32Bit
 *  or you get an Fatal exception (9)
 * @param data uint8_t *
 * @param size uint32_t
 */
void SPIClass::writeBytes(uint8_t * data, uint32_t size)
{
    spiTransferBytes(_spi, data, 0, size);
}

/**
 * @param data uint8_t * data buffer. can be NULL for Read Only operation
 * @param out  uint8_t * output buffer. can be NULL for Write Only operation
 * @param size uint32_t
 */
void SPIClass::transferBytes(uint8_t * data, uint8_t * out, uint32_t size)
{
    spiTransferBytes(_spi, data, out, size);
}

/**
 * Note:
 *  data need to be aligned to 32Bit
 *  or you get an Fatal exception (9)
 * @param data uint8_t *
 * @param size uint8_t  max for size is 64Byte
 * @param repeat uint32_t
 */
void SPIClass::writePattern(uint8_t * data, uint8_t size, uint32_t repeat)
{
    if(size > 64) {
        return;    //max Hardware FIFO
    }

    uint32_t byte = (size * repeat);
    uint8_t r = (64 / size);

    while(byte) {
        if(byte > 64) {
            writePattern_(data, size, r);
            byte -= 64;
        } else {
            writePattern_(data, size, (byte / size));
            byte = 0;
        }
    }
}

void SPIClass::writePattern_(uint8_t * data, uint8_t size, uint8_t repeat)
{
    uint8_t bytes = (size * repeat);
    uint8_t buffer[64];
    uint8_t * bufferPtr = &buffer[0];
    uint8_t * dataPtr;
    uint8_t dataSize = bytes;
    for(uint8_t i = 0; i < repeat; i++) {
        dataSize = size;
        dataPtr = data;
        while(dataSize--) {
            *bufferPtr = *dataPtr;
            dataPtr++;
            bufferPtr++;
        }
    }

    writeBytes(&buffer[0], bytes);
}

SPIClass SPI(VSPI);