Pixels_SPIhw.h

/*
    Pixels. Graphics library for TFT displays.

    Copyright (C) 2012-2013  Igor Repinetski

    The code is written in C/C++ for Arduino and can be easily ported to any microcontroller by rewritting the low level pin access functions.

    Text output methods of the library rely on Pixelmeister's font data format. See: http://pd4ml.com/pixelmeister

    This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/3.0/

    This library includes some code portions and algoritmic ideas derived from works of
    - Andreas Schiffler -- aschiffler at ferzkopp dot net (SDL_gfx Project)
    - K. Townsend http://microBuilder.eu (lpc1343codebase Project)
*/

/*
    Hardware SPI layer (SCL=13, SDA=11 on Arduino)
*/

#include "Pixels.h"

#ifdef PIXELS_MAIN
#error Pixels_SPIhw.h must be included before Pixels_<CONTROLLER>.h
#endif

#ifndef PIXELS_SPIHW_H
#define PIXELS_SPIHW_H

#define SPI_CLOCK_DIV4 0x00
#define SPI_CLOCK_DIV16 0x01
//#define SPI_CLOCK_DIV64 0x02
#define SPI_CLOCK_DIV128 0x03
#define SPI_CLOCK_DIV2 0x04
#define SPI_CLOCK_DIV8 0x05
#define SPI_CLOCK_DIV32 0x06
#define SPI_CLOCK_DIV64 0x07

#define SPI_MODE0 0x00
#define SPI_MODE1 0x04
#define SPI_MODE2 0x08
#define SPI_MODE3 0x0C

#define SPI_MODE_MASK 0x0C  // CPOL = bit 3, CPHA = bit 2 on SPCR
#define SPI_CLOCK_MASK 0x03  // SPR1 = bit 1, SPR0 = bit 0 on SPCR
#define SPI_2XCLOCK_MASK 0x01  // SPI2X = bit 0 on SPSR

#define SPI(X) SPDR=X;while(!(SPSR&_BV(SPIF)))

class SPIhw
{
  private:
    uint8_t pinSCL;
    uint8_t pinSDA;
    uint8_t pinWR;
    uint8_t pinCS;
    uint8_t pinRST;

    regtype *registerSCL;
    regtype *registerSDA;
    regtype *registerWR;
    regsize bitmaskSCL;
    regsize bitmaskSDA;
    regsize bitmaskWR;

    void beginSPI();
    void endSPI();

    bool eightBit;

  protected:
    void reset() {
        digitalWrite(pinRST, LOW);
        delay(100);
        digitalWrite(pinRST, HIGH);
        delay(100);
    }

    void writeCmd(uint8_t b);
    __attribute__((noinline)) void writeData(uint8_t data); // noinline saves 4-5kb sketch code in the case. An impact to performance is to be learned.

    void writeData(uint8_t hi, uint8_t lo) {
        writeData(hi);
        writeData(lo);
    }

    void writeDataTwice(uint8_t b) {
        writeData(b);
        writeData(b);
    }

    void writeCmdData(uint8_t cmd, uint16_t data) {
        writeCmd(cmd);
        writeData(highByte(data));
        writeData(lowByte(data));
    }

  public:
    void setSPIBitOrder(uint8_t bitOrder);
    void setSPIDataMode(uint8_t mode);
    void setSPIClockDivider(uint8_t rate);
//    void setSPIEightBit(bool bits) {
//        eightBit = bits;
//    }

    /**
        Overrides SPI pins
        @param scl
        @param sda
        @param cs chip select
        @param rst reset
        @param wr write pin; if not omitted (and not equals to 255) - switches to eight bit mode transfer
    */
    inline void setSpiPins(uint8_t scl, uint8_t sda, uint8_t cs, uint8_t rst, uint8_t wr = 255) {
        pinSCL = scl;
        pinSDA = sda;
        pinCS = cs;
        pinRST = rst;
        pinWR = wr;
        eightBit = wr != 255;
    }

    /**
        Overrides PPI pins
        @param cs chip select
    */
    inline void setPpiPins(uint8_t rs, uint8_t wr, uint8_t cs, uint8_t rst, uint8_t rd) {
    }

    inline void registerSelect() {
    }

    void initInterface();
};

void SPIhw::initInterface()
{
    registerSCL  = portOutputRegister(digitalPinToPort(pinSCL));
    bitmaskSCL  = digitalPinToBitMask(pinSCL);
    registerSDA = portOutputRegister(digitalPinToPort(pinSDA));
    bitmaskSDA  = digitalPinToBitMask(pinSDA);
    registerWR  = portOutputRegister(digitalPinToPort(pinWR));
    bitmaskWR = digitalPinToBitMask(pinWR);
    registerCS  = portOutputRegister(digitalPinToPort(pinCS));
    bitmaskCS = digitalPinToBitMask(pinCS);

    pinMode(pinSCL, OUTPUT);
    pinMode(pinSDA, OUTPUT);
    pinMode(pinWR, OUTPUT);
    pinMode(pinRST, OUTPUT);
    pinMode(pinCS, OUTPUT);

    reset();

    setSPIBitOrder(MSBFIRST);
    setSPIDataMode(SPI_MODE3);
    //  setSPIClockDivider(SPI_CLOCK_DIV64);
    beginSPI();
}

void SPIhw::writeCmd(uint8_t cmd)
{
    if (eightBit)
    {
        *registerWR &= ~bitmaskWR;
    }
    else
    {
        SPCR &= ~_BV(SPE); // Disable SPI to get control of the SCK pin.
        cbi(registerSDA, bitmaskSDA);
        cbi(registerSCL, bitmaskSCL);   // Pull SPI SCK high
        //  delay(1);   // Insert extra time to the hight pulse, typically needed
        sbi(registerSCL, bitmaskSCL);   // Pull SPI SCK low
        SPCR |= _BV(SPE);      // Enable SPI again
    }

#if defined(TEENSYDUINO) || defined(GLOWDECK)
    SPI0_SR = SPI_SR_TCF;
    SPI0_PUSHR = cmd;
    while (!(SPI0_SR & SPI_SR_TCF)) ; // wait
#else
    SPDR = cmd;
    while (!(SPSR & _BV(SPIF)));
#endif
}

void SPIhw::writeData(uint8_t data)
{
    if (eightBit)
    {
        *registerWR |= bitmaskWR;
    }
    else
    {
        SPCR &= ~_BV(SPE); // Disable SPI to get control of the SCK pin.
        sbi(registerSDA, bitmaskSDA);
        cbi(registerSCL, bitmaskSCL);   // Pull SPI SCK high
        //  delay(1);   // Insert extra time to the hight pulse, typically needed
        sbi(registerSCL, bitmaskSCL);   // Pull SPI SCK low
        SPCR |= _BV(SPE);      // Enable SPI again
    }

#if defined(TEENSYDUINO) || defined(GLOWDECK)
    SPI0_SR = SPI_SR_TCF;
    SPI0_PUSHR = data;
    while (!(SPI0_SR & SPI_SR_TCF)) ; // wait
#else
    SPDR = data;
    while (!(SPSR & _BV(SPIF)));
#endif
}

void SPIhw::beginSPI()
{
    cbi(registerSCL, bitmaskSCL);
    cbi(registerSDA, bitmaskSDA);
    digitalWrite(pinCS, HIGH);

    // Warning: if the SS pin ever becomes a LOW INPUT then SPI
    // automatically switches to Slave, so the data direction of
    // the SS pin MUST be kept as OUTPUT.

    SPCR |= _BV(MSTR);
    SPCR |= _BV(SPE);

#if defined(TEENSYDUINO) || defined(GLOWDECK)
    uint32_t ctar = SPI_CTAR_FMSZ(7) |
                    SPI_CTAR_PBR(0) | SPI_CTAR_BR(0) | SPI_CTAR_CSSCK(0) | SPI_CTAR_DBR;

    SPI0_MCR = SPI_MCR_MDIS | SPI_MCR_HALT | SPI_MCR_PCSIS(0x1F);
    SPI0_CTAR0 = ctar;
    SPI0_CTAR1 = ctar | SPI_CTAR_FMSZ(8);
    SPI0_MCR = SPI_MCR_MSTR | SPI_MCR_PCSIS(0x1F);
#else
    DDRB = DDRB | B00000001; // PB0 as OUTPUT
    PORTB = PORTB | B00000001; // PB0 as HIGH
#endif
}

void SPIhw::endSPI()
{
    SPCR &= ~_BV(SPE);
}

void SPIhw::setSPIBitOrder(uint8_t bitOrder)
{
    if (bitOrder == LSBFIRST)
    {
        SPCR |= _BV(DORD);
    }
    else
    {
        SPCR &= ~(_BV(DORD));
    }
}

void SPIhw::setSPIDataMode(uint8_t mode)
{
    SPCR = (SPCR & ~SPI_MODE_MASK) | mode;
}

void SPIhw::setSPIClockDivider(uint8_t rate)
{
    SPCR = (SPCR & ~SPI_CLOCK_MASK) | (rate & SPI_CLOCK_MASK);
    SPSR = (SPSR & ~SPI_2XCLOCK_MASK) | ((rate >> 2) & SPI_2XCLOCK_MASK);
}
#endif