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Concerto SPI2 interface problem

Stefan Buechner
Intellectual 815 points

Hi all,

I'm desperately triying to get my SPI to work on SSI2. Maybe someone has some idea in which trap I run into...

It is configured to run on PortB (GPIO8..10). After initialization the periphery when I send data, the MOSI signal is working fine but the CLK signal is missing!

Here is my initialization function:

void SSI2_Init( void )
{
  SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);
  SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
  // Set the pins to be controlled by the SSI controller.
  GPIOPinConfigure(GPIO_PB0_SSI2TX);
  GPIOPinConfigure(GPIO_PB1_SSI2RX);
  GPIOPinConfigure(GPIO_PB2_SSI2CLK);

  // CS-EPCS_FLASH
  GPIOPinTypeGPIOOutput(GPIO_PORTB_BASE, GPIO_PIN_3);
  GPIOPinWrite(GPIO_PORTB_BASE, GPIO_PIN_3, 0xFF);
  // CS-EEPROM
  GPIOPinTypeGPIOOutput(GPIO_PORTA_BASE, GPIO_PIN_6);
  GPIOPinWrite(GPIO_PORTA_BASE, GPIO_PIN_6, 0xFF);
  // CS-RTC
  GPIOPinTypeGPIOOutput(GPIO_PORTA_BASE, GPIO_PIN_4);
  GPIOPinWrite(GPIO_PORTA_BASE, GPIO_PIN_4, 0xFF);

  // Enable SSI peripheral
  SysCtlPeripheralEnable(SYSCTL_PERIPH_SSI2);
  SysCtlPeripheralReset(SYSCTL_PERIPH_SSI2);

  GPIOPinTypeSSI(GPIO_PORTB_BASE, GPIO_PIN_2 | GPIO_PIN_1 | GPIO_PIN_0);

  SSIConfigSetExpClk(SSI2_BASE, SysCtlClockGet(SYSTEM_CLOCK_SPEED),
                     SSI_FRF_MOTO_MODE_0,
                     SSI_MODE_MASTER, USER_BITRATE, 8);

  IntEnable(INT_SSI2);
  SSIIntEnable(SSI2_BASE, SSI_RXFF|SSI_RXTO);
  SSIEnable(SSI2_BASE);
}

Best regards,
Stefan
  • 0
    Intellectual 815 points

    Problem solved recently. It was a bit tricky, the other master (FPGA) was kept in a config-mode but did not give me control over all SPI signals, missed an remark in the user guide of the FPGA.

    Another thing which I run into while searching for the problem: When I read some registers (e.g. GPIODATA or SSISR) I don't get the value I expect. I have to read the content to an variable. Just to take care of when you are debugging...

    Stefan