path: root/firmware/drivers/spi.c

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/***************************************************************************
 *            spi.c
 *
 *  Sun Jun  9 14:02:49 CEST 2013
 *  Copyright 2013 Bent Bisballe Nyeng
 *  deva@aasimon.org
 ****************************************************************************/

/*
 *  This file is part of Pedal2Metal.
 *
 *  Pedal2Metal is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  Pedal2Metal 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with Pedal2Metal; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
 */
#include "spi.h"

#include <LPC17xx.h>

#if 0

#define USE_CMSIS

#ifdef USE_CMSIS
#include <lpc17xx_spi.h>
#include <lpc17xx_pinsel.h>

LPC_SPI_TypeDef *spi;
#else/*USE_CMSIS*/

// SPI power bit in PCONP register (see table 46)
#define PCSPI_BIT 8

// SPI clock bits (16 and 17) in PCLKSEL0 register (see table 40)
#define PCLK_SPI_BIT 16

// Clock speed devisors. Values for PCLKSEL0 register (See table 42)
typedef enum {
  CCLK_4 = 0x0, // 00: PCLK_peripheral = CCLK/4
  CCLK_1 = 0x1, // 01: PCLK_peripheral = CCLK
  CCLK_2 = 0x2, // 10: PCLK_peripheral = CCLK/2
  CCLK_8 = 0x3, // 11: PCLK_peripheral = CCLK/8
} ClockDevisor;

// PINSEL0 function value for SCK0 function (see table 79)
#define SCK0_FUNCTION 0x2
#define SCK0_BIT 30

// PINSEL1 function value for SSEL0 function (see table 80)
#define SSEL0_FUNCTION 0x2
#define SSEL0_BIT 0

// PINSEL1 function value for MISO0 function (see table 80)
#define MISO0_FUNCTION 0x2
#define MISO0_BIT 2

// PINSEL1 function value for MOSI0 function (see table 80)
#define MOSI0_FUNCTION 0x2
#define MOSI0_BIT 4

#endif/*USE_CMSIS*/

/**
 * Initialisation as described in "17.1 Basic Configuration"
 */
void spi_init()
{
#ifdef USE_CMSIS
  SPI_CFG_Type spi_cfg;

  // 16 bit data transfers
	spi_cfg.Databit = SPI_DATABIT_8;

	// WM8523 samples bits on rising edges. Mode 0 or 3 will work
	// http://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus#Clock_polarity_and_phase

	// Mode 0
	spi_cfg.CPHA = SPI_CPHA_FIRST; // 0
	spi_cfg.CPOL = SPI_CPOL_HI; // 0
	/*
	// Mode 3
	spi_cfg.CPHA = SPI_CPHA_SECOND; // 1
	spi_cfg.CPOL = SPI_CPOL_LO; // 1
	*/

	// We are the master
	spi_cfg.Mode = SPI_MASTER_MODE;

	// We run on a little endian mcu.
	spi_cfg.DataOrder = SPI_DATA_MSB_FIRST;

	// Se WM8523 manual page 14. Min clock pulse width 40ns ~= 25MHz
	spi_cfg.ClockRate = 10000;//1000000000; // 1MHz

  spi = LPC_SPI;
	SPI_Init(spi, &spi_cfg);

  NVIC_EnableIRQ(SPI_IRQn);

#else/*USE_CMSIS*/
  // Power up the SPI bus.
  // Remark: On reset, the SPI is enabled (PCSPI = 1).
  LPC_SC->PCONP |= (1 << PCSPI_BIT); // set bit 8 in PCONP (PCSPI bit)

  // Set clock speed (indirectly as clock devisor)
  ClockDevisor clk = CCLK_8; 
  LPC_SC->PCLKSEL0 &= ~(0x3 << PCLK_SPI_BIT);
  LPC_SC->PCLKSEL0 |= ((clk & 0x3) << PCLK_SPI_BIT); // set bit 16 and 17 in PCLKSEL0

  // Make pin selection for SPI.
  // SCK0:  P0.15
  // SSEL0: P0.16
  // MOSI0: P0.17
  // MISO0: P0.18
  LPC_PINCON->PINSEL0 &= ~(0x3 << SCK0_BIT);
  LPC_PINCON->PINSEL0 |= (SCK0_FUNCTION << SCK0_BIT);

  LPC_PINCON->PINSEL1 &= ~(0x3 << SSEL0_BIT);
  LPC_PINCON->PINSEL1 |= (SSEL0_FUNCTION << SSEL0_BIT);

  LPC_PINCON->PINSEL1 &= ~(0x3 << MISO0_BIT);
  LPC_PINCON->PINSEL1 |= (MISO0_FUNCTION << MISO0_BIT);

  LPC_PINCON->PINSEL1 &= ~(0x3 << MOSI0_BIT);
  LPC_PINCON->PINSEL1 |= (MOSI0_FUNCTION << MOSI0_BIT);

  // Enable SPI interrupt:
  // Set SPI interrupt flag (see table 367)
  LPC_SPI->SPINT = 1;

  // Enable SPI interrupt in the NVIC (see table 50)
  NVIC_EnableIRQ(SPI_IRQn);
#endif/*USE_CMSIS*/

  // Configure SSEL pin:
  LPC_GPIO0->FIODIR |= 1 << 16; // Set P0.16 in output mode

}

void spi_deinit()
{
#ifdef USE_CMSIS
#else/*USE_CMSIS*/
  // Power down SPI
  LPC_SC->PCONP &= ~(1 << PCSPI_BIT); // unset bit 8 in PCONP (PCSPI bit)
#endif/*USE_CMSIS*/
}

// S0SPCR register (see table 361)
#define BENA 0 // Enable more than 8 bit transactions
#define CPHA 0 // CPHA (Clock Phase Control)     \ _ Mode 0
#define CPOL 0 // CPOL (Clock Polarity Control)  /
#define MSTR 1 // MSTR (Master Mode Select)
#define LSB  1 // LSB vs MSB
#define SPIE 1 // Enable interrupts
#define BITS 0 // Bits to transfer, only use if BENA is set to 1
void spi_configure()
{
#ifdef USE_CMSIS
#else/*USE_CMSIS*/
  // S0SPCR register (see table 361)
  LPC_SPI->SPCR = (BENA << 2) | (CPHA << 3) | (CPOL << 4) | (MSTR << 5) |
    (LSB  << 6) | (SPIE << 7) | (BITS << 8);

  LPC_SPI->SPCCR = 1;
#endif/*USE_CMSIS*/
}

static volatile int spi_done = 0;
static void spi_mark_as_done()
{
  spi_done = 1;
}

volatile int temp;
void __delay(uint32_t del)
{
    uint32_t i;
    for(i=0;i<del;i++)
        temp = i;
}

void spi_read_write(uint8_t *tx_data, uint8_t *rx_data, size_t length)
{
#ifdef USE_CMSIS

  SPI_DATA_SETUP_Type dst;
  dst.tx_data = tx_data;
  dst.rx_data = rx_data;
  dst.length = length;
  dst.counter = 0;
  dst.status = 0;
  dst.callback = spi_mark_as_done;

  SPI_ClearIntPending(spi);
  LPC_GPIO0->FIOPIN &= ~( 1 << 16 ); // make P0.16 low

  spi_done = 0;
  SPI_ReadWrite(spi, &dst, SPI_TRANSFER_POLLING);//SPI_TRANSFER_INTERRUPT);

  //  cli_write(">");
  while (!(SPI_GetStatus(spi) & SPI_SPSR_SPIF)) { }
  //while(!spi_done) {}
  //cli_write("<");

  LPC_GPIO0->FIOPIN |= 1 << 16; // make P0.16 high

#else/*USE_CMSIS*/

  int i = 0;
  //  cli_write(">>");

  LPC_GPIO0->FIOPIN &= ~( 1 << 16 ); // make P0.16 low

  for(; i < length; i++) {
    /*
    cli_write("w");
    LPC_GPIO0->FIOPIN &= ~( 1 << 16 ); // make P0.16 low
    __delay(1 << 23);
    */

    //LPC_SPI->SPINT = 1; // Clear interrupt (see section 17.7.7)
    //if(LPC_SPI->SPSR) {} // Make sure we clear the status register

    LPC_SPI->SPDR = tx_data[i];

    //cli_write("[%d]", tx_data[i]);

    //if(LPC_SPI->SPSR) {} // Make sure we clear the status register

    // Check SPIF bit (see table 362)
    //while(((LPC_SPI->SPSR << 7) & 0x1) != 1) {}
    //while(LPC_SPI->SPSR == 0) {} // Wait for status register
    while(LPC_SPI->SPINT == 0) {} // Wait for interrupt
    LPC_SPI->SPINT = 1;
    //__delay(1 << 23);

    // cli_write("{%d}", LPC_SPI->SPSR);

    rx_data[i] = LPC_SPI->SPDR;
    //cli_write("[%d]", rx_data[i]);

    /*
    cli_write("r");
    LPC_GPIO0->FIOPIN |= 1 << 16; // make P0.16 high
    __delay(1 << 23);
    */
  }

  LPC_GPIO0->FIOPIN |= 1 << 16; // make P0.16 high

  //cli_write("<<");
#endif/*USE_CMSIS*/
}

#endif/*0*/