path: root/firmware/spi.c

/*
 * Author: Benedikt Sauter <sauter@ixbat.de>
 * All rights reserved.
 *
 * Short descripton of file:
 *
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions 
 * are met:
 *
 *   * Redistributions of source code must retain the above copyright 
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above 
 *     copyright notice, this list of conditions and the following 
 *     disclaimer in the documentation and/or other materials provided 
 *     with the distribution.
 *   * Neither the name of the FH Augsburg nor the names of its 
 *     contributors may be used to endorse or promote products derived 
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#include "common.h"
#include "protocol.h"

#include "spi.h"


void spi_parser(char *buf)
{
  switch(buf[0]) {
    case CMD_SPI_INIT:
      spi_init_usb(buf[2], buf[3], buf[4]);
      break;
    case CMD_SPI_DEINIT:
      spi_deinit_usb();
      break;
    case CMD_SPI_SEND:
      spi_send_usb(buf[2], &buf[3]);
      break;
    case CMD_SPI_RECV:
      spi_receive_usb((int)buf[2]);
    case CMD_SPI_SEND_AND_RECV:
      spi_send_and_receive_usb(&buf[3], (int)buf[2]);
      break;
    default:
      answer[0] = buf[0];
      answer[1] = RSP_UNKOWN_CMD;
      answer[2] = 0;
      CommandAnswer(3);
  }
}

void spi_init_usb(uint8_t dord, uint8_t mode, uint8_t speed)
{
  answer[0] = CMD_SPI_INIT;
  answer[1] = (unsigned char) spi_init(dord, mode, speed);
  answer[2] = 0;
  CommandAnswer(3);
}


int spi_init(uint8_t dord, uint8_t mode, uint8_t speed)
{
  uint8_t cpol, cpha, spr1, spr0, spi2x;

  dord = dord ? 1 : 0;

  switch(mode)
  {
    case 0:
      cpol = 0;
      cpha = 0;
      break;
    case 1:
      cpol = 0;
      cpha = 1;
      break;
    case 2:
      cpol = 1;
      cpha = 0;
      break;
    case 3:
      cpol = 1;
      cpha = 1;
      break;
    default:
      return RSP_ERROR;
  }

  switch(speed)
  {
    case SPI_SPEED_125kHz:
      spi2x = 0;
      spr1  = 1;
      spr0  = 1;
      break;
    case SPI_SPEED_250kHz:
      spi2x = 0;
      spr1  = 1;
      spr0  = 0;
      break;
    case SPI_SPEED_500kHz:
      spi2x = 1;
      spr1  = 1;
      spr0  = 0;
      break;
    case SPI_SPEED_1MHz:
      spi2x = 0;
      spr1  = 0;
      spr0  = 1;
      break;
    case SPI_SPEED_2MHz:
      spi2x = 1;
      spr1  = 0;
      spr0  = 1;
      break;
    case SPI_SPEED_4MHz:
      spi2x = 0;
      spr1  = 0;
      spr0  = 0;
      break;
    case SPI_SPEED_8MHz:
      spi2x = 1;
      spr1  = 0;
      spr0  = 0;
      break;
    default:
      return RSP_ERROR;
  }

  // MOSI, SCK: out/low
  // MISO:      in
  DDRB  &=  ~(1 << MISO);
  DDRB  |=   (1 << MOSI | 1 << SCK); 
  PORTB &=  ~(1 << MOSI | 1 << MISO | 1 << SCK);  // SCK has to be low in IDLE

  // SPE:  SPI enable
  // DORD: Data Order (0: starting with LSB)
  // MSTR: Master mode
  // SPR1, SPR2, SPI2X: speed
  SPCR = (1 << SPE | dord << DORD | 1 << MSTR | cpol << CPOL | cpha << CPHA |
          spr1 << SPR1 | spr0 << SPR0);
  SPSR = (spi2x << SPI2X);

  octopus.ports[5] = PIN_SCK;
  octopus.ports[6] = PIN_MOSI;
  octopus.ports[7] = PIN_MISO;

  return RSP_OK;
}

void spi_deinit_usb(void)
{
  answer[0] = CMD_SPI_DEINIT;
  answer[1] = (unsigned char)spi_deinit();
  answer[2] = 0;

  CommandAnswer(3);
}

int spi_deinit(void)
{
  SPCR = 0;
  SPSR = 0;

  octopus.ports[5] = PIN_NONE;
  octopus.ports[6] = PIN_NONE;
  octopus.ports[7] = PIN_NONE;

  return RSP_OK;
}


void spi_send_usb(uint8_t length, char * buf)
{
  answer[0] = CMD_SPI_SEND;
  answer[1] = (unsigned char)spi_send(length, buf);
  answer[2] = 0;

  CommandAnswer(3);
}

int spi_send(int length, char * buf)
{
  uint8_t i;
  for(i = 0; i < length; i++)
  {
    SPDR = buf[i];
    while(!(SPSR & (1 << SPIF)));
  }
  return RSP_OK;
}


void spi_receive_usb(int length)
{
  answer[0]        = CMD_SPI_RECV;
  answer[1]        = (unsigned char)spi_receive(length, (char*)&answer[2]);
  answer[2+length] = 0;
  CommandAnswer(3+length);
}


unsigned char spi_receive(int length, char * buf)
{
  int i;
  int timeout = 0;

  for(i = 0; i < length; i++)
  {
    SPDR = 0;
    while(!(SPSR & (1 << SPIF))) 
    {
      if(timeout++ > 1000) 
        return RSP_TIMEOUT;
    }
    buf[i] = SPDR;
  }

  return RSP_OK;
}

void spi_send_and_receive_usb(char * txbuf, int length)
{
  answer[0]=CMD_SPI_SEND;
  answer[1]=(unsigned char)spi_send_and_receive(txbuf,(char *)&answer[2],length);
  answer[2+length]=0;
  CommandAnswer(3+length);

}

int spi_send_and_receive(char * txbuf, char * rxbuf, int length){

  int i, timeout=0;
  for(i=0;i<length;i++){
    SPDR = txbuf[i];
    //while ( !(SPSR & (1 << SPIF)) ) ;
    while(!(SPSR & (1 << SPIF))) { timeout++; if( timeout > 1000) return RSP_TIMEOUT; }
    rxbuf[i]=SPDR;
  }
  return RSP_OK;
}