UART example acting weird

[molviken]

Hi! 

I've been playing around with the SDK and nrf9160 dk for a week now, and it's a lot of fun. 

In the beginning the UART example worked perfectly, and I managed to add a second UART which also worked. Now, after playing around with mqtt, trying to merge some of the projects etc. it seems something broke. 

When i try to run the UART feedback example (using printk with LTE link monitor), it doesn't work. The monitor shows: "UART feedback loop" as supposed, but nothing can be written to it.

When running the "at_client" example, I can write as many commands as I'd like (at least after restarting the monitor if UART example was previously tried).

Any suggestions?

My prj.conf:

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CONFIG_SERIAL=y

CONFIG_TRUSTED_EXECUTION_NONSECURE=y

CONFIG_UART_INTERRUPT_DRIVEN=y

CONFIG_MAIN_STACK_SIZE=4096

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

main.c: 

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#include <zephyr.h>

#include <sys/printk.h>

#include <drivers/uart.h>

static u8_t uart_buf[1024];

void uart_cb(struct device *x)

{

uart_irq_update(x);

int data_length = 0;

if (uart_irq_rx_ready(x)) {

data_length = uart_fifo_read(x, uart_buf, sizeof(uart_buf));

uart_buf[data_length] = 0;

}

printk("%s", uart_buf);

}

void main(void)

{

struct device *uart = device_get_binding("UART_0");

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#include <zephyr.h>
#include <sys/printk.h>
#include <drivers/uart.h>

static u8_t uart_buf[1024];

void uart_cb(struct device *x)
{
	uart_irq_update(x);
	int data_length = 0;

	if (uart_irq_rx_ready(x)) {
		data_length = uart_fifo_read(x, uart_buf, sizeof(uart_buf));
		uart_buf[data_length] = 0;
	}
	printk("%s", uart_buf);
}

void main(void)
{
	struct device *uart = device_get_binding("UART_0");

	uart_irq_callback_set(uart, uart_cb);
	uart_irq_rx_enable(uart);
	printk("UART loopback start!\n");
        printk("u sucks\n");
        printk("u sucks more\n");
	while (1) {
		k_cpu_idle();
	}
}

The solution might be obvious as I am probably having a big case of tunnel visions.

Any suggestions?