TMS320F28388D: Unable to set interrupt priority in CM causing assert fail in FreeRTOS

Hi Kevin,

Let me loop in the FreeRTOS expert to take a look at this question.

Best Regards,

Delaney

Hi Kevin, 

The compiler error is due to a version mismatch in the projectspec, you can replace your C2000Ware/kernel/FreeRTOS/Demo/C2000_F2838x_CM_CCS/CCS folder with the one linked below. (This just updates the ARM compiler version, if there is still a mismatch, you can open up the projectspec file in a text editor and manually update to your installed version. This should be resolved in the next SDK release)

5658.CCS.zip

Regd. the issue with Interrupt_setPriority(), how are you passing the priority for the UART interrupt, and how are you reading it back?  I am not able to recreate your issue.

Regards, 

Arnav

Hi Arnav

This is the code to initialize the port, called from main. This is largely taken from example code:

//! @note: Must be >= configMAX_SYSCALL_INTERRUPT_PRIORITY!!
static uint8_t UART_ISR_PRIORITY = ( 0xc0 );    // priority 6 (6 << 7)

void DbgPortInit(uint32_t uartBase)
{
    // configure uart
    UART_setConfig(uartBase, UART_CLK_FREQ, baudRate, 
        (UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE | UART_CONFIG_PAR_NONE));
    // Enable the UART0 interrupt on the processor (NVIC).
    UART_registerInterrupt(INT_UART0, UART_ISR);
    // set interrupt priority
    Interrupt_setPriority(INT_UART0, UART_ISR_PRIORITY);
    // FIFO enable
    UART_enableFIFO(uartBase);
    UART_setFIFOLevel(UART0_BASE, UART_FIFO_TX1_8, UART_FIFO_RX1_8);

    // Receive interrupt configuration
    UART_clearInterruptStatus(UART0_BASE, UART_INT_RX | UART_INT_RT);
    UART_enableInterrupt(UART0_BASE, UART_INT_RX);
}

This is the ISR, again, largely from example code:

__interrupt void UART_ISR(void)
{
    uint32_t isrStat = UART_getInterruptStatus(uartBase, UART_RAW_INT);
    char ch;
    BaseType_t higherPriorityTaskWoken;
    
    if ((isrStat & (uint32_t)UART_INT_RX) == (uint32_t)UART_INT_RX) {

        while (UART_isDataAvailable(uartBase)) {
            
            ch = (char)UART_readCharNonBlocking(uartBase);
            xQueueSendFromISR(portRxQueue, &ch, &higherPriorityTaskWoken);
        }
    }


    if ((isrStat & (uint32_t)UART_INT_TX) == (uint32_t)UART_INT_TX) {
        while (UART_isSpaceAvailable(uartBase)) {
            if (xQueueReceiveFromISR(portTxQueue, &ch, &higherPriorityTaskWoken)) {
                UART_writeCharNonBlocking(uartBase, (uint8_t)ch);   
            }
            else {
                // queue empty disable further tx interrupts
                UART_disableInterrupt(uartBase, UART_INT_TX);
            }
        }
    }

    UART_clearInterruptStatus(uartBase, isrStat);
    portYIELD_FROM_ISR(higherPriorityTaskWoken);
}

When either xQueueSendFromISR() or xQueueReceiveFromISR() is called, the processor halts on the assert on line 589 or port.c:

            configASSERT( ucCurrentPriority >= ucMaxSysCallPriority );

In CCS, ucCurrentPriority is 0, as is the NVIC register.

The code that you provided does not build. I get this linker error (which is what happened in my project when I bypassed the CCS project import):

 undefined                      first referenced                       
  symbol                            in file                            
 ---------                      ----------------                       
 vPortValidateInterruptPriority ./third_party/FreeRTOS/Source/queue.obj

I added this to FreeRTOSConfig.h to get it to build:

#include "assert.h"
#define configASSERT(x) assert(x)

But now I get the assert fail. But, if I just do

#define configASSERT

Then it builds, but the CPU hangs in the ISR.