Receiving data from GPS L80 with nrf52832 via UART

RE: Receiving data from GPS L80 with nrf52832 via UART

awneil — Thu, 18 Jul 2019 08:22:09 GMT

[quote userid="81573" url="~/f/nordic-q-a/49769/receiving-data-from-gps-l80-with-nrf52832-via-uart/199124"]I am giving the command "$PMTK225,4*2F\r\n"[/quote]

That is not what the code you posted had!

[quote userid="81573" url="~/f/nordic-q-a/49769/receiving-data-from-gps-l80-with-nrf52832-via-uart/199124"]I think that by using this code "while (app_uart_put(txBuff[i]) != NRF_SUCCESS);" I am not able to send the command.[/quote]

So what actually happens?

What do you see coming from the UART when you run the code?

Have you stepped the code in the debugger to see what is actually going on?

RE: Receiving data from GPS L80 with nrf52832 via UART

Utkarsh — Thu, 18 Jul 2019 07:29:53 GMT

Yes sir you are right, I am giving the command "$PMTK225,4*2F\r\n" , this command is supposed to send the GPS L80 module in the backup mode, i.e., it should stop transmitting anything. But I think that by using this code "while (app_uart_put(txBuff[i]) != NRF_SUCCESS);" I am not able to send the command. This statement should send the string char by char to the GPS until the controller returns NRF_SUCCESS which indicates that the whole string is sent and the GPS should go in backup mode, but it's not happening and the GPS is showing no response. What should I do sir?

RE: Receiving data from GPS L80 with nrf52832 via UART

awneil — Wed, 17 Jul 2019 18:03:01 GMT

[quote userid="81573" url="~/f/nordic-q-a/49769/receiving-data-from-gps-l80-with-nrf52832-via-uart/199072"] I am not able to send the whole string at one time[/quote]

Why not - what prevents you ?

What were you expecting to happen?

What is actually happening?

Have you stepped through your code in the debugger to see what's going on?

In particular, what do you think this is going to do:

while (app_uart_put(txBuff[i]) != NRF_SUCCESS);

I don't think your command string is correct:

char txBuff[]="$PMTK225,4*2F<CR><LF>";

Instead of "<CR><LF>" I think you mean "\r\n" ... ?

RE: Receiving data from GPS L80 with nrf52832 via UART

Utkarsh — Wed, 17 Jul 2019 17:29:16 GMT

Hi sir,

I executed it and now it is working fine, but now I am trying to communicate with GPS L80 by trying to send its PMTK commands. I converted the command into a string so that nrf52832 controller transmits the whole string at a time and the GPS can execute the command but I am not able to send the whole string at one time, I am using the ble_app_uart code please can you help me? I am attaching the code.

Regards

#define MCU_TX 23
#define MCU_RX 24
int main(void)
{
uint8_t rxBuff[10];
    char txBuff[]="$PMTK225,4*2F<CR><LF>";
    app_uart_flush();
    while (true)
    {
    for(int i=0;i<22;i++){
        while (app_uart_put(txBuff[i]) != NRF_SUCCESS);
        }
        nrf_delay_ms(2000);
         }
         }

RE: Receiving data from GPS L80 with nrf52832 via UART

Utkarsh — Tue, 16 Jul 2019 10:17:52 GMT

Thanks sir, I'll try the same and get back to you.

RE: Receiving data from GPS L80 with nrf52832 via UART

Utkarsh — Tue, 16 Jul 2019 10:17:40 GMT

Thanks sir, I'll try the same and get back to you.

RE: Receiving data from GPS L80 with nrf52832 via UART

awneil — Tue, 16 Jul 2019 08:19:44 GMT

[quote userid="81573" url="~/f/nordic-q-a/49769/receiving-data-from-gps-l80-with-nrf52832-via-uart/198633"]The uart1 structure when running the code shows everything that I have set[/quote]

But it doesn't show how you have physically connected to your GPS unit.

[quote userid="81573" url="~/f/nordic-q-a/49769/receiving-data-from-gps-l80-with-nrf52832-via-uart/198633"] I tried to interconnect Tx and Rx of the board to see that if I am transmitting something, am I getting that back again[/quote]

The next step is to connect to an external USB-to-UART, and verify that you can both send and receive over that.

This will prove:

That you can correctly configure the pins
That you can correctly set the baud rate
That you can correctly identify which is "Tx" and which is "Rx"

A simple loopback doesn't confirm any of those.

See here for more tips on serial debugging:

https://www.avrfreaks.net/comment/2306116#comment-2306116

https://www.avrfreaks.net/comment/2336161#comment-2336161

Note the use of two terminals - so that you can see both Rx & Tx data ...

RE: Receiving data from GPS L80 with nrf52832 via UART

Jørgen Holmefjord — Tue, 16 Jul 2019 08:18:02 GMT

The NRF_UART_Type is a reference to the actual hardware registers for the UART peripheral. You have created a new instance, but it will reference a random location in RAM. It will show the values you assign it, but these values will not be written to the registers. Replace &uart1 in the function calls with the already defined instance reference, NRF_UART0.

RE: Receiving data from GPS L80 with nrf52832 via UART

Utkarsh — Tue, 16 Jul 2019 08:10:48 GMT

Hello.

I have run the already given UART example from examples/peripheral/uart and it seems to work fine. I tried to interconnect Tx and Rx of the board to see that if I am transmitting something, am I getting that back again. The uart1 structure when running the code shows everything that I have set i.e Tx and Rx pins that I have set manually also Tx data i.e 1 (just to check) but still I am getting getting 0 at Rx and also the buadrate is not been set. I am attaching the code as well as the snapshot of the uart1 structure when watched in watch. Please help.

/**
 * Copyright (c) 2014 - 2019, Nordic Semiconductor ASA
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form, except as embedded into a Nordic
 *    Semiconductor ASA integrated circuit in a product or a software update for
 *    such product, must reproduce the above copyright notice, this list of
 *    conditions and the following disclaimer in the documentation and/or other
 *    materials provided with the distribution.
 *
 * 3. Neither the name of Nordic Semiconductor ASA nor the names of its
 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * 4. This software, with or without modification, must only be used with a
 *    Nordic Semiconductor ASA integrated circuit.
 *
 * 5. Any software provided in binary form under this license must not be reverse
 *    engineered, decompiled, modified and/or disassembled.
 *
 * THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
/** @file
 * @defgroup uart_example_main main.c
 * @{
 * @ingroup uart_example
 * @brief UART Example Application main file.
 *
 * This file contains the source code for a sample application using UART.
 *
 */

#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include "app_uart.h"
#include "app_error.h"
#include "nrf_delay.h"
#include "nrf.h"
#include "bsp.h"
#include "nrf_uart.h"

NRF_UART_Type uart1;

//#define ENABLE_LOOPBACK_TEST  /**< if defined, then this example will be a loopback test, which means that TX should be connected to RX to get data loopback. */

/*#define MAX_TEST_DATA_BYTES     (15U)                *< max number of test bytes to be used for tx and rx. */
#define UART_TX_BUF_SIZE 256                         *< UART TX buffer size. */
#define UART_RX_BUF_SIZE 256                         *< UART RX buffer size. */
#define uart1_rx NRF_GPIO_PIN_MAP(0,22)
#define uart1_tx NRF_GPIO_PIN_MAP(0,23)
uint8_t tx_data = 1;
uint8_t rx_data;

void uart_error_handle(app_uart_evt_t * p_event)
{
    if (p_event->evt_type == APP_UART_COMMUNICATION_ERROR)
    {
        APP_ERROR_HANDLER(p_event->data.error_communication);
    }
    else if (p_event->evt_type == APP_UART_FIFO_ERROR)
    {
        APP_ERROR_HANDLER(p_event->data.error_code);
    }
}



/* When UART is used for communication with the host do not use flow control.*/
#define UART_HWFC APP_UART_FLOW_CONTROL_DISABLED
#endif


/**
 * @brief Function for main application entry.
 */
int main(void)
{
    nrf_uart_enable(&uart1);
    nrf_uart_txrx_pins_set(&uart1, uart1_tx, uart1_rx);
    nrf_uart_baudrate_set(&uart1,NRF_UART_BAUDRATE_115200);

char UART_RX_BUF[256];
int i=0;
    while (i<256)
    {   
        nrf_uart_txd_set(&uart1,tx_data);
        rx_data = nrf_uart_rxd_get(&uart1);
        i++;
    }

}

Regards

RE: Receiving data from GPS L80 with nrf52832 via UART

Jørgen Holmefjord — Mon, 15 Jul 2019 13:48:49 GMT

Hi,

You do not assign any useful value to uart1. You should rather pass the existing symbol of NRF_UART_Type that is defined in nrf52.h: NRF_UART0.

Best regards,
Jørgen

RE: Receiving data from GPS L80 with nrf52832 via UART

awneil — Mon, 15 Jul 2019 13:24:53 GMT

[quote userid="81573" url="~/f/nordic-q-a/49769/receiving-data-from-gps-l80-with-nrf52832-via-uart"]the nrf52832 board[/quote]

What nrf52832 board, exactly ?

If it's Nordic's nRF52832-DK, remember that it has a USB-to-UART converter occupying some pins ...

https://devzone.nordicsemi.com/f/nordic-q-a/49703/connecting-uart-data-to-development-board-pca10040/198110#198110

[quote userid="81573" url="~/f/nordic-q-a/49769/receiving-data-from-gps-l80-with-nrf52832-via-uart"]I am not able to receive anything.[/quote]

Before adding the complications of 3rd-party external devices, have you tried the UART example in the SDK, and got that working?

[quote userid="81573" url="~/f/nordic-q-a/49769/receiving-data-from-gps-l80-with-nrf52832-via-uart"]I connected the Rx of nrf52832 with GPS and vice versa[/quote]

How did you connect it, exactly?

Show a schematic - trying to describe connections in text highly ineffective!

How to properly post source code: