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Configuring UART_1 for nRF9160

Hi Dev Team,

I was working with the nRF9160 and started off with the basic UART sample found here : https://github.com/Rallare/fw-nrfconnect-nrf/tree/nrf9160_samples/samples/nrf9160/uart

I wanted to configure the UART_1 to connect to an external sensor, and I followed some links : https://devzone.nordicsemi.com/f/nordic-q-a/45476/connecting-uart1-to-a-periph-on-nrf9160-dk/178988#178988, https://devzone.nordicsemi.com/f/nordic-q-a/57199/using-the-nrf9160-to-send-and-receive-data-over-rs485-using-uart and changed the prj.conf file and the overlays file.

prj.conf:

CONFIG_NEWLIB_LIBC=y
CONFIG_LIBLIGHTMODBUS=y


CONFIG_SERIAL=y
CONFIG_TRUSTED_EXECUTION_NONSECURE=y
CONFIG_UART_INTERRUPT_DRIVEN=y
CONFIG_MAIN_STACK_SIZE=4096

CONFIG_COMPILER_OPT="-DNRFX_UARTE_ENABLED=1 -DNRFX_UARTE0_ENABLED=1"


CONFIG_UART_1_NRF_UARTE=y

CONFIG_UART_1_NRF_FLOW_CONTROL=y

#CONFIG_BOARD_NRF9160DK_UART0_ARDUINO=y

#CONFIG_BOARD_NRF9160DK_UART0_VCOM=n

nrf9160dk_nrf9160ns.overlay:

/* Needed to get NRF_PWMn defined. */
&pwm1 {
	status = "okay";
};

&pwm2 {
	status = "okay";
};

&pwm3 {
	status = "okay";
};


&uart1 {
	current-speed = <9600>;
	status = "okay";
	tx-pin = <1>;
	rx-pin = <0>;
	rts-pin = <14>;
	cts-pin = <15>;
};

&uart0 {
	current-speed = <9600>;
	status = "ok";
	tx-pin = <10>;
	rx-pin = <11>;
	rts-pin = <12>;
	cts-pin = <13>;
};

The same is defined as an nrf9160dk_nrf9160.overlay file in the SPM folder.

When I try to build my application, I get a Kconfig error regarding the CONFIG_UART_1_NRF_UARTE=y. Could you help me understand what more could be required to change for it to work for UART_0.

Regards,

Adeel.

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Simon over 5 years ago in reply to Adeel +1 verified

If you set the VDD IO switch to 3V the GPIO will output 3V and if you set it to 1v8, it will output 1.8v. I tested this with a multimeter and P0.28, I've attached the sample below: devzone.nordicsemi…

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0 Simon over 5 years ago
In NCS v1.3.0 the configurations CONFIG_UART_<x>_NRF_UARTE are not directly user-configurable and you can not set them in the prj.conf file. These configurations will get their value from the Device Tree. E.g. if you have enabled uart1 in the overlay file (status="okay"), the configuration UART_1_NRF_UARTE will get enabled here.

So in short, just removed CONFIG_UART_1_NRF_UARTE from prj.conf.

Another thing to be aware of is that UART1 will automatically get routed to VCOM2 due to this. In order to avoid this, flash the nRF9160dk_nrf52840 (on the nRF9160DK) with a hello world sample with this configuration:

BOARD_NRF9160DK_UART1_ARDUINO=y BOARD_NRF9160DK_UART1_VCOM=n

Best regards,

Simon
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0 Adeel over 5 years ago in reply to Simon

Hi Simon,

Okay. I understood the first part.

I try to flash the hello world example and I first switch the SW5 to nrf52. Then I add your configurations to the prj.conf file. But when I load the project, it again gives me KConfig errors here as well.

This is when I try to build the hello world sample to flash for nRF9160dk_nrf52840. Is there something I am missing again.

2287.board_controller_uart1.hex . I found this file from another post : https://devzone.nordicsemi.com/f/nordic-q-a/45476/connecting-uart1-to-a-periph-on-nrf9160-dk/178988#178988. Could I use this directly to flash the nRF9160dk_nrf52840 board ?

Regards,

Adeel.
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0 Adeel over 5 years ago in reply to Adeel

Hi Simon,

I tried another example that looked much simpler and I just wanted to transmit things out of the UART.

The code is pretty straight forward as well to understand.

static K_FIFO_DEFINE(fifo_uart_tx_data);
static K_FIFO_DEFINE(fifo_uart_rx_data);

struct uart_data_t {
	void  *fifo_reserved;
	u8_t    data[1024];
	u16_t   len;
};

static struct device *uart_dev;


void uart_cb(struct device *x)
{
	uart_irq_update(x); // Start processing interrupts in ISR.
	int data_length = 0;

	if (uart_irq_rx_ready(x)) { // Check if UART RX buffer has a received char.               
		data_length = uart_fifo_read(x, uart_buf, sizeof(uart_buf)); // Read data from FIFO.
		uart_buf[data_length] = 0;
                }
                printk("Received data is:%s\r\n", uart_buf);

            if (uart_irq_tx_ready(x)) {
            
                struct uart_data_t *buf = 
                k_fifo_get(&fifo_uart_tx_data, K_NO_WAIT);
              u16_t written = 0;

              /* Nothing in the FIFO, nothing to send */
		if (!buf) {
			uart_irq_tx_disable(x);
			return;
		}

                while (buf->len > written) {
			written += uart_fifo_fill(x,
						  &buf->data[written],
						  buf->len - written);
                       uart_tx(uart_dev, buf, 5, 5000);
		}

                while (!uart_irq_tx_complete(x)) {
			/* Wait for the last byte to get
			 * shifted out of the module
			 */
		}

		if (k_fifo_is_empty(&fifo_uart_tx_data)) {
			uart_irq_tx_disable(x);
		}

                k_free(buf);

      
              
}
}

void main(void)
{
       

        uart_dev = device_get_binding("UART_2"); 
        if (!uart_dev) {
		printk("error\r\n");
	}          

        uart_irq_rx_disable(uart_dev);
        uart_irq_callback_set(uart_dev, uart_cb); // Set UART interrupt callback
        uart_irq_rx_enable(uart_dev);

        uart_irq_tx_enable(uart_dev);

        printk("Testing1: \n");              
        uart_fifo_fill(uart_dev, "AB" ,sizeof("AB"));
        
        k_sleep(K_MSEC(100));


        
	while (1) {
                
                  k_cpu_idle();             
                
	}
}

Still, I don't see the data out on my analyzer. I have a serial interface analyzer where I view the string. I tried with Arduino and that worked just by a transmit signal.

So, I am unsure as to what could be the causes for it. I can see the loopback data in this example as well when I connect my Tx to Rx.

(1). I have the correct overlay files both in spm (nrf9160dk_nrf9160) as well as in my folder (nrf9160dk_nrf9160ns)

&uart2 {
	compatible = "nordic,nrf-uarte";
	status = "okay";
	current-speed = <9600>;
	tx-pin = <10>;
	rx-pin = <11>;
	rts-pin = <12>;
	cts-pin = <13>;
	hw-flow-control;
};

&uart1 {
	status = "disabled";
};

I have also changed the configuration in the nrf9160dk_nrf9160_common.dts file in : C:\Users\adeel\ncs\v1.3.0\zephyr\boards\arm\nrf9160dk_nrf9160.

My prj config file is :

CONFIG_UART_INTERRUPT_DRIVEN=y
CONFIG_UART_ASYNC_API=y
CONFIG_TRUSTED_EXECUTION_NONSECURE=y
CONFIG_UART_INTERRUPT_DRIVEN=y
CONFIG_MAIN_STACK_SIZE=4096
CONFIG_UART_2_NRF_FLOW_CONTROL=y

I am unsure of what could be the issue ? The configuration or the code.

I just want to transmit the string set in uart_fifo_fill() function in my code to check the UART connection.

Regards,

Adeel.

0 Simon over 5 years ago in reply to Adeel

Sorry for the delay on this, I've been quite busy lately. I will look into it today. Have you made any progress?

Best regards,

Simon
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0 Adeel over 5 years ago in reply to Simon

Hi Simon,

Not really. I could not figure out the exact trouble with it. The loopback works with Tx to Rx. So I assume that the string is atleast reaching the Tx.

I followed this post and got a simple example : https://devzone.nordicsemi.com/f/nordic-q-a/47218/continuously-package-send-on-uart

The string transmission to an outside serial interface is not happening. I wonder what could be the cause.

When I just take out and put back my Tx pin on the board, I see random data on the serial analyser. I am sure the RS485 configuration is correct because for now, I just want to transmit the string. The DE is kept high for that and RE high as well (Negative logic). Any insights would be helpful.

I hope there is no mistake in my UART config atleast.

Regards,

Adeel.
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0 Adeel over 5 years ago in reply to Adeel

Hi Simon,

Just to catch up on this, I read about the enable and the blocking mode. I believe the blocking mode after transmission is not being set up.

I have enabled the DE and RE pin before transmission and I wait for a certain time before making it low.

I found this case quite relevant: https://devzone.nordicsemi.com/f/nordic-q-a/55059/nrf51822-with-modbus-ttl-to-rs485/223289#223289

But it has handlers which I did not find compatible with nrf9160. Its for the nRF52 series.

Could you just help me in modifying my above attached example that could be compatible with the nrf9160DK. I would really appreciate the help in this.

Regards,

Adeel.
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0 Adeel over 5 years ago in reply to Adeel

Hi Simon,

Any help on this would be very useful :).

Regards,

Adeel.
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0 Adeel over 5 years ago in reply to Adeel

Hi Simon,

Any help on this would be very useful :).

Regards,

Adeel.
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0 Simon over 5 years ago in reply to Adeel

I'm really sorry for the delay on this, I've been quite busy lately. I will look into this tomorrow.

Best regards,

Simon
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0 Adeel over 5 years ago in reply to Simon

Hi Simon,

Thanks a lot. Sure, It would be really helpful .

Regards,

Adeel.
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0 Simon over 5 years ago in reply to Adeel
Why don't you start really simple, follow these steps:

Program this sample onto the nRF9160: 0755.uart_main.zip

Using NCS v1.3.0 an the board nrf9160dk_nrf9160ns

I disabled flow control as well

Connect the nRF9160 to the RS485 as shown in the image below:

Best regards,

Simon
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0 Adeel over 5 years ago in reply to Simon

Hi Simon,

I tried this config that you told me. Attaching the picture of it.

I connected Tx to my configured input P0.10. I also changed the number in the overlay.

DE,RE are connected to 5V of other Arduino.

I still don't see anything out.

I was expecting the received strings at the receiver device.

Any inputs ? I just changed the Tx pin as P0.10 in overlay and baudrate to 9600. My receiver device has the same baud arte of 9600.

Regards,

Adeel.
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0 Simon over 5 years ago in reply to Adeel

Try connecting all the pins to the same board (nrf9160dk), as shown in the image. Not to the Arduino's
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