ESP32 Forum

Posted: **Mon Aug 12, 2024 5:04 am**

Hi all,

Asking here since I'm not getting any response on the ESP32 forum on the Micropython site:

ESP-IDF version: v5.1.2-dirty

I have a custom board design that uses an ESP32-PICO-D4. On this board is a SC16IS752 dual SPI UART, accessed from MP via a custom C module. I have found that characters are dropped, particularly at higher baud rates, due to the time that MP GPIO interrupts require. So, I would like to have the UART received character interrupt served via a FreeRTOS task, Adding a test function that creates a task that blinks an LED while running in parallel with the MP task was not a problem, however when trying to add support for a GPIO interrupt to service the UART IRQ I found that portYIELD_FROM_ISR() was preventing the module from successfully linking, generating the following error message:

spisvc.c:(.iram1.0+0x21): undefined reference to traceISR_EXIT_TO_SCHEDULER

Here is the relevant part of the task that sets up the interrupt handler:

Code: [Select all] [Expand/Collapse]

    gpio_isr_handler_add(GPIO_NUM_34, spi_uart_isr_handler, NULL);
    
    for (;;) {
       xSemaphoreTake(spi_svc_sem, portMAX_DELAY);
       gpio_set_level(GPIO_NUM_12, 1);
       spisvc_uart_rx_fifos();
       gpio_set_level(GPIO_NUM_12, 0);
    }

GeSHi © Codebox Plus Extension

And here is the (barebones) handler itself:

Code: [Select all] [Expand/Collapse]

void spi_uart_isr_handler(void *param)
{
    static BaseType_t xHigherPriorityTaskWoken = pdFALSE;
        
    xSemaphoreGiveFromISR(spi_svc_sem, &xHigherPriorityTaskWoken);
    if( xHigherPriorityTaskWoken) {
        portYIELD_FROM_ISR(); 
    }
}

If I comment out portYIELD_FROM_ISR() it compiles and links without a problem, I'm assuming I need to link to some library or include some header that defines traceISR_EXIT_TO_SCHEDULER?

If I add a call to vTaskDelay() there are no problems, so it doesn't seem to be a FreeRTOS library issue.

Any help greatly appreciated!

ESP32 Forum

port_YIELD_FROM_ISR() in custom C module for micropython causing linker error

port_YIELD_FROM_ISR() in custom C module for micropython causing linker error