Need to get nRF 9151 UART <=> IOT to work

[RamizB]

hello,

I have nRF9151 and would like to connect UART1  (Rx PO.28 & Tx PO.29) to an external IOT device.  it only supports the Tx/Rx port. There is HW control.

My goal is to send one character 'A' on the port and then receive 2 characters. i can't make it to work. I followed the instructions to configure the device but not able to make it work!

Attached provide the configuration of application with simply loop at the to do the actual Tx/Tx and would greatly appreciate any help to make this work for me.

Thanks for your help in advance.

regards

Ramizblinky-UART.zip

[RamizB]

Thanks...setting CONFIG_UART_USE_RUNTIME_CONFIGURE=y certainly enabled the UART!..awesome

also changed the filename as directed (did not make impact).

i will be texting Tx/Rx msgs

[Vidar Berg]

Excellent. 

RamizB said:

also changed the filename as directed (did not make impact).

Yes, the overlay file (nrf9161dk_nrf9161_ns.overlay) in the project you uploaded was empty anyway, so it would not make any difference if it got included in the build or not.

[RamizB]

Vidar,  so much for your help. Things are working a bit bitter.  I am able to make the Tx port work (i.e i can send signal on the Tx PO.29 and receive it on the MCU).  However the nrf can't see message coming from the MCU (on PO.28).  i tested with different cables - no impact. i tried to connect PO.28 to PO.29 - did not make a difference. i tried with nrf9161 and nrf9151 - did not make a difference. 

In the debug mode i don't get the event UART_RX_RDY in the uart_cb function.  Kindly appreciate your help and advice.

Thanks for your help in advance.

Attached is the code along with config files.native_tty-UART.zip

[RamizB]

prj.conf
CONFIG_GPIO=y
#CONFIG_UART_INTERRUPT_DRIVEN=n
CONFIG_TFM_SECURE_UART=n
CONFIG_TFM_LOG_LEVEL_SILENCE=y
CONFIG_UART_USE_RUNTIME_CONFIGURE=y
# Enable UART driver support
CONFIG_UART_ASYNC_API=n
CONFIG_UART_INTERRUPT_DRIVEN=n
CONFIG_SERIAL=y
CONFIG_UART_NRFX=y
# CONFIG_UART_1=y


# Logging (optional for debugging)
CONFIG_LOG=y
CONFIG_LOG_DEFAULT_LEVEL=3
CONFIG_UART_CONSOLE=y
# Enable minimal kernel settings
CONFIG_THREAD_STACK_INFO=y


# Kernel options
CONFIG_MAIN_STACK_SIZE=1024
CONFIG_HEAP_MEM_POOL_SIZE=4096
CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048
===========================================
nrf9161dk_nrf9161_ns.overlay
&uart0 {
    status = "okay";
};

=============================================
main.c





#include <zephyr/kernel.h>
#include <zephyr/device.h>
#include <zephyr/drivers/uart.h>
#include <zephyr/sys/printk.h>
#include <string.h>
#include <stdio.h>


#define UART_DEVICE_NODE DT_NODELABEL(uart0)  // Replace 'uart0' with your UART node label
#define BUFFER_SIZE 32

static const struct device *uart_dev;
static uint8_t rx_buffer[BUFFER_SIZE];
static uint8_t tx_buffer[BUFFER_SIZE];

struct uart_config uart_cfg = {
    .baudrate = 9600,
    .data_bits = UART_CFG_DATA_BITS_8,
    .parity = UART_CFG_PARITY_NONE,
    .stop_bits = UART_CFG_STOP_BITS_1,
    .flow_ctrl = UART_CFG_FLOW_CTRL_NONE,

};

void uart_poll_init() {

    int rc;

    uart_dev = DEVICE_DT_GET(UART_DEVICE_NODE);
    if (!device_is_ready(uart_dev)) {
        printk("UART device not ready\n");
        return;
    }

    rc = uart_configure(uart_dev, &uart_cfg);
    if (rc != 0) {
        printf("Could not configure device uart1\n");
    } else {
        printf("Configure device uart1\n");
    }

    printf("UART initialized successfully\n");
}

void uart_poll_write(const uint8_t *data, size_t length) {
    for (size_t i = 0; i < length; i++) {
        uart_poll_out(uart_dev, data[i]);
    }
}

size_t uart_poll_read(uint8_t *buffer, size_t buffer_len) {
    size_t bytes_read = 0;
    int received_byte;

    while (bytes_read < buffer_len) {
        received_byte = uart_poll_in(uart_dev, &buffer[bytes_read]);
        if (received_byte == 0) {  // 0 indicates a byte was successfully read
            bytes_read++;
        } else {
            break;  // Exit loop if no more data is available
        }
    }

    return bytes_read;
}

int main(void) {

    uart_poll_init();

    strcpy((char *)tx_buffer, "Hello, UART!\n");
    uart_poll_write(tx_buffer, strlen((char *)tx_buffer));

    printf("Waiting for UART input...\n");

    while (1) {
        size_t len = uart_poll_read(rx_buffer, BUFFER_SIZE);
        if (len > 0) {
            rx_buffer[len] = '\0';  // Null-terminate the received string
            printf("Received: %s\n", rx_buffer);

//        k_sleep(K_MSEC(1));  // Poll every 100 ms
    }
}

why uart0 Rx pollin read 7 bytes only.docx

Thanks for your help. I was able to get Tx work but not the Rx. So, switch my scheme to use the polling method to the Tx/Rx.  this worked per the following code.  However. i was able to get receive ONLY 7 Character! 

in my application the MCU generates a long sream (1000-2000 characters); but i am only receiving 7 characters!

after much search i thought that the rx_buffer is the controller factor for how many charters can be received.

but then i discover this article from Nordic Support AI. how to solve this issue?  I need to be able to receive large number of charters!

[Vidar Berg]

Hi, 

I recommend using the Asynchronous API from the UART driver. This allows you to utilize DMA for receiving data in the background.

Best regards,

Vidar