CC2652R7: Trying to write to SSI address space (0x40000000) causes hard fault.

Hi Mike,

Have you stepped through your code or used print logs to determine exactly which of these code lines causes the hard fault?  You could still reference the resources inside of C:\ti\simplelink_cc13xx_cc26xx_sdk_7_10_01_24\source\ti\drivers\spi\SPICC26X2DMA.c to better understand the intended setup and usage.  This includes flushing Fifos as well as disabling SSI operations and module interrupts within initHw. 

/*
 *  ======== initHw ========
 */
static void initHw(SPI_Handle handle)
{
    ClockP_FreqHz freq;
    SPICC26X2DMA_Object *object         = handle->object;
    SPICC26X2DMA_HWAttrs const *hwAttrs = handle->hwAttrs;

    flushFifos(hwAttrs);

    /* Disable SSI operation */
    SSIDisable(hwAttrs->baseAddr);

    /* Disable SPI module interrupts */
    SSIIntDisable(hwAttrs->baseAddr, SSI_RXOR | SSI_RXFF | SSI_RXTO | SSI_TXFF);
    SSIIntClear(hwAttrs->baseAddr, SSI_RXOR | SSI_RXTO);

    /* Set the SPI configuration */
    ClockP_getCpuFreq(&freq);
    SSIConfigSetExpClk(hwAttrs->baseAddr, freq.lo, object->format, object->mode, object->bitRate, object->dataSize);
}

You could also add simplelink_cc13xx_cc26xx_sdk_7_10_01_24\source\ti\devices\cc13x2x7_cc26x2x7\driverlib\ssi.c (for example) directly to your project to build this resource with your project and further debug SSIConfigSetExpClk, among other functions.

Regards,
Ryan

Hi Ryan,

Thank you for your response. Yes I've stepped through my code, even at the disassembly level. I've tried rearranging calls, etc. It always fails on the first access to the registers relative to the base address of 0x40000000. For example, SSIDisable(SSI0_BASE) will fail here:

HWREG(ui32Base + SSI_O_CR1) &= ~(SSI_CR1_SSE);

Where "ui32Base + SSI_O_CR1" is 0x40000004. It generates a HardFault exception as if 0x40000004 is an invalid address.

Are you having issues establishing any other peripherals (ADC, Timers, UART, etc)?  Make sure the Power, Clock, and GPIO dependencies are properly initialized beforehand (referring to their TI Driver -> Driverlib initialization instances accordingly).  It's possible to step through the spicontroller FreeRTOS example to further understand the recommended process.

Regards,
Ryan

Thanks for pointing me to this example! Hopefully it will help me understand what I'm missing.