ESP32 Forum

Posted: **Sun Nov 20, 2016 11:38 pm**

hi guys


#define UART_FIFO_LEN           (128)        /*!< Length of the hardware FIFO buffers */

how much we can set fifo for uart in extrem example and how much you suggest for max?
can we read, reset overflow bit by user?
reset Fifo after read by user ?

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uart_reg->int_clr.txfifo_empty = 1;
uart_reg->int_ena.txfifo_empty = 1;

best wishes
rudi

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//Event of HW FIFO overflow detected
                  case UART_FIFO_OVF:
                      ESP_LOGI(TAG, "hw fifo overflow\n");
                      break;

btw, we have rxfifo and txfifo,
hw fifo respekt UART_FIFO_OVF means allways rxfifo ?

btw: CAN Register works just in time pefekt ( 1000 msg )
only uart hw fifo ovf - have not insert fifo reset after INTR.

: hw fifo overflow.png (10.46 KiB) Viewed 16082 times

Posted: **Mon Nov 21, 2016 4:04 am**

Max is 128. The idea is to set threshold on number of bytes before the interrupt is triggered.

Posted: **Wed Nov 23, 2016 10:06 am**

WiFive wrote:Max is 128. The idea is to set threshold on number of bytes before the interrupt is triggered.

txs, WiFive,
do you or folks know from head how can hw Fifo check fast and clear the bit?
( src ? / info ? )

( i search just in time this and for controll the ring buffer )
i play with this
and see not the clear doing for hw Fifo. perhabs to much fog for my

the event "hw Fifo" can be processed - how/where i can find this info ?

best wishes
rudi

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} else if(uart_intr_status & UART_RXFIFO_OVF_INT_ST_M) {
            UART_ENTER_CRITICAL_ISR(&uart_spinlock[uart_num]);
            uart_reg->conf0.rxfifo_rst = 1;
            uart_reg->conf0.rxfifo_rst = 0;
            uart_reg->int_clr.rxfifo_ovf = 1;
            UART_EXIT_CRITICAL_ISR(&uart_spinlock[uart_num]);
            uart_event.type = UART_FIFO_OVF;

clear..all other..

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else {
            uart_reg->int_clr.val = uart_intr_status; /*simply clear all other intr status*/
            uart_event.type = UART_EVENT_MAX;

?

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uart_reg->int_clr.val = UART_RXFIFO_FULL_INT_CLR_M | UART_RXFIFO_TOUT_INT_CLR_M;

Posted: **Wed Nov 23, 2016 11:34 am**

hi

where is UART defined?

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uart_dev_t* uart_reg = UART[uart_num];

txs
best wishes
rudi

Posted: **Wed Nov 23, 2016 11:45 am**

rudi ;-) wrote:hi

where is UART defined?
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uart_dev_t* uart_reg = UART[uart_num];
txs
best wishes
rudi

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// static const char* UART_TAG = "UART";
static uart_dev_t* UART[UART_NUM_MAX] = {&UART0, &UART1, &UART2};
..
...

int ValReg = 0;
      int uart_num = (int)pvParameters;
      uart_event_t event;
	  uart_dev_t* uart_reg = UART[uart_num];  // yeap..

Posted: **Wed Nov 23, 2016 2:15 pm**

hi,
when/where we must do this?
in the ISR after clear the bits?

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uart_flush(uart_num);

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esp_err_t uart_flush(uart_port_t uart_num)
{
    UART_CHECK((uart_num < UART_NUM_MAX), "uart_num error", ESP_FAIL);
    UART_CHECK((p_uart_obj[uart_num]), "uart driver error", ESP_FAIL);
    uart_obj_t* p_uart = p_uart_obj[uart_num];
    uint8_t* data;
    size_t size;

    //rx sem protect the ring buffer read related functions
    xSemaphoreTake(p_uart->rx_mux, (portTickType)portMAX_DELAY);
    ESP_INTR_DISABLE(p_uart->intr_num);
    while(true) {
        if(p_uart->rx_head_ptr) {
            vRingbufferReturnItem(p_uart->rx_ring_buf, p_uart->rx_head_ptr);
            p_uart->rx_ptr = NULL;
            p_uart->rx_cur_remain = 0;
            p_uart->rx_head_ptr = NULL;
        }
        data = (uint8_t*) xRingbufferReceive(p_uart->rx_ring_buf, &size, (portTickType) 0);
        if(data == NULL) {
            break;
        }
        vRingbufferReturnItem(p_uart->rx_ring_buf, data);
    }
    p_uart->rx_ptr = NULL;
    p_uart->rx_cur_remain = 0;
    p_uart->rx_head_ptr = NULL;
    ESP_INTR_ENABLE(p_uart->intr_num);
    xSemaphoreGive(p_uart->rx_mux);

    if(p_uart->tx_buf_size > 0) {
        xSemaphoreTake(p_uart->tx_mux, (portTickType)portMAX_DELAY);
        ESP_INTR_DISABLE(p_uart->intr_num);
        UART_ENTER_CRITICAL(&uart_spinlock[uart_num]);
        UART[uart_num]->int_ena.txfifo_empty = 0;
        UART[uart_num]->int_clr.txfifo_empty = 1;
        UART_EXIT_CRITICAL(&uart_spinlock[uart_num]);
        do {
            data = (uint8_t*) xRingbufferReceive(p_uart->tx_ring_buf, &size, (portTickType) 0);
            if(data == NULL) {
                break;
            }
            vRingbufferReturnItem(p_uart->rx_ring_buf, data);
        } while(1);
        p_uart->tx_brk_flg = 0;
        p_uart->tx_brk_len = 0;
        p_uart->tx_head = NULL;
        p_uart->tx_len_cur = 0;
        p_uart->tx_len_tot = 0;
        p_uart->tx_ptr = NULL;
        p_uart->tx_waiting_brk = 0;
        p_uart->tx_waiting_fifo = false;
        ESP_INTR_ENABLE(p_uart->intr_num);
        xSemaphoreGive(p_uart->tx_mux);
    }
    uart_reset_fifo(uart_num);
    return ESP_OK;
}

Posted: **Wed Nov 23, 2016 8:24 pm**

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..
static esp_err_t uart_reset_fifo(uart_port_t uart_num);
..
..

//Event of HW FIFO overflow detected
                  case UART_FIFO_OVF:
                      ESP_LOGI(TAG, "hw fifo overflow\n");
					  // uart_reg->int_clr.val = UART_RXFIFO_FULL_INT_CLR_M | UART_RXFIFO_TOUT_INT_CLR_M;
					  
					  // UART_RXFIFO_OVF_INT_ST_M
					  uart_reg->int_clr.val = UART_RXFIFO_OVF_INT_ST_M;
					  
					  reg_delay();
					  ESP_LOGI(TAG, "cleared..\n");
					  
					   uart_flush(uart_num);
					   ESP_LOGI(TAG, "uart_flush cleared..\n");
					  
					  // reset
					   uart_reset_fifo(uart_num);
					   ESP_LOGI(TAG, "fifo reset\r\n");
					  
					  break;
                  //Event of UART ring buffer full
                  case UART_BUFFER_FULL:
                      ESP_LOGI(TAG, "ring buffer full\n");
                      
					  
					  uart_reg->int_clr.val = UART_RXFIFO_OVF_INT_ST_M;
					  reg_delay();
					  ESP_LOGI(TAG, "ringbuffer int cleared..\n");
					  break;

...

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..../build/main\libmain.a(uart_main.o):(.literal.uart_task+0x64): undefined reference to `uart_reset_fifo'

Posted: **Wed Nov 23, 2016 9:00 pm**

It is not exported in UART.h

But really you are supposed to design UART code to avoid overflow for expected data stream. You may need to interrupt more frequently to empty the fifo into the ring buffer or make a bigger ring buffer or use hw/sw flow control or wait for DMA support.

Posted: **Thu Nov 24, 2016 1:13 am**

WiFive wrote:It is not exported in UART.h

But really you are supposed to design UART code to avoid overflow for expected data stream. You may need to interrupt more frequently to empty the fifo into the ring buffer or make a bigger ring buffer or use hw/sw flow control or wait for DMA support.

thank you WiFive,
i do now a delay between the send data - and for first - it works - the fifo ovf do not fire now
but the (ring) buffer i think is too small, there are missings thing ( last picture )

i have test the example uart code with task.
now i try to build/design the UART code to avoid overflow for expected data stream, also the ring buffer.

i saw the UHCI (=uart dma )in the 1.0 plan - this would be a goal for this too

i will try to handle the things now ( ring buffer, fifo ) - must deeper read .

the good things are, that the register write/clear now ok without mistake.
i do this after each write/clear and it helps:

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void reg_delay (void) {
	__asm__ __volatile__("nop;nop;nop;nop;nop;nop;nop;nop;");
}

best wishes
rudi

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hw fifo overflow max set / reset

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