CAN-Controller MCP2515 per SPI an ATM128

Hallo,


ich versuche vergeblich den CAN-SPI-Adapter zum Laufen zu bringen.:
(Code komplett im Anhang)


int main(void)
{
  SW_DDR &= ~(1 << SW0);
  SW_DDR &= ~(1 << SW1);
  SW_PORT |= (1 << SW0);
  SW_PORT |= (1 << SW1);

  LED_DDR |= (1 << LED);   // LED auf Ausgang
  LED_PORT &= ~(1 << LED); // LED EIN


  initLCD();      // LCD-Display initialisieren
  init_SPI_Master();    // SPI initialisieren

  LCD_TextOut(" Init ");

  initMCP2515();

  LED_PORT |= (1 << LED); // LED AUS
}



int8_t initMCP2515(void)
{
  uint8_t test;
  char testtext[]= " .: ";

  // Software-Reset durchführen
  SPI_PORT &= ~(1<<SPI_SS);
  asm("nop");
  SPI_TX(MCP2515_RESET);
  asm("nop");
  SPI_PORT |= (1<<SPI_SS);

  MCP2515_WRREG(MCP2515_CNF1,5);
  asm("nop");
  test = MCP2515_RDREG(MCP2515_CNF1);

  testtext[1]=test+48;
  LCD_TextOut(testtext);

  if (test == 5)
  {
    LCD_TextOut("match");
  }
  else
  {
    LCD_TextOut("fail");
  }

  test = MCP2515_READ_STATUS();
  testtext[1]=test+48;
  LCD_TextOut(testtext);

  return 0;
}

uint8_t MCP2515_WRREG(uint8_t Adresse, uint8_t Daten)
{
  SPI_PORT &= ~(1<<SPI_SS);
  asm("nop");
  SPI_TX(MCP2515_WRITE);
  asm("nop");
  SPI_TX(Adresse);
  asm("nop");
  SPI_TX(Daten);
  asm("nop");
  SPI_PORT |= (1<<SPI_SS);

  return 0;
}

uint8_t MCP2515_RDREG(uint8_t Adresse)
{
  uint8_t Daten;
  SPI_PORT &= ~(1<<SPI_SS);
  asm("nop");
  SPI_TX(MCP2515_READ);
  asm("nop");
  SPI_TX(Adresse);
  asm("nop");
  Daten= SPI_PUT(0xff);

  SPI_PORT |= (1<<SPI_SS);

  return Daten;
}

uint8_t MCP2515_READ_STATUS()
{
  uint8_t Daten;
  SPI_PORT &= ~(1<<SPI_SS);
  asm("nop");
  SPI_TX(MCP2515_READ_STAT);
  asm("nop");
  Daten= SPI_PUT(0xff);
  SPI_PORT |= (1<<SPI_SS);
}

int8_t init_SPI_Master(void)
{
  /* Set MOSI and SCK output, all others input */
  SPI_DDR |= ((1<<SPI_MOSI)|(1<<SPI_SCK)|(1<<SPI_SS));
  SPI_PORT &= ~((1<<SPI_SCK)|(1<<SPI_MOSI)|(1<<SPI_MISO));
  SPI_PORT |= (1<<SPI_SS);

  /* Enable SPI, Master, set clock rate fck/16 */
  SPCR = ((1<<SPE)|(1<<MSTR)|(1<<SPR0));//|(1<<SPR1));
  //SPSR = (1<<SPI2X);
  return 0;
}

int8_t SPI_TX(int8_t cData)
{
  /* Start transmission */
  SPDR = cData;
  /* Wait for transmission complete */
  while(!(SPSR & (1<<SPIF)))
  ;
  return 0;
}

int8_t SPI_RX(void)
{
  return SPDR;
}

uint8_t SPI_PUT(uint8_t cData)
{
  /* Start transmission */
  SPDR = cData;
  /* Wait for transmission complete */
  while(!(SPSR & (1<<SPIF)))
  ;
  return SPDR;
}

hat da vielleicht jemand einen Tipp, woran es liegen könnte? Ausgabe ist 
immer "0"!

MFG
Matthias