Help with basic implementation of UART

[Deep Patel]

Hello,

I am working on developing a BLE peripheral FW (Reader) with NRF52840 using nRF Connect SDK 2.0.0. The Reader has two MCU, one is BLE MCU and other is the main Control MCU.

I have implemented my custom BLE service in the BLE FW. 

Some data that i received from BLE Client i have to send to Main MCU using UART and also Some data that i receive on UART from Control MCU i have to send to BLE Client probably.

Which is the easiest method to achieve this from a sample ?

I have read the peripheral_uart example, but that seems to be more complex than what i need. It implements every data on UART to BLE Client.

Also, i am not much clear the steps to configure, init and use UART functions.

I am reading through samples and responses from devzone since 2 days, but havent got a good understanding on how to start yet.

Please help.

[Deep Patel]

Hello .. any help ? I need to get this to work asap. 

I have reference from peripheral_lpuart example and use it in my project as : 

LOG_MODULE_REGISTER(uart);

const struct device *lpuart = DEVICE_DT_GET(DT_NODELABEL(lpuart));

int uart_init(void)
{
	if (!device_is_ready(lpuart)) 
	{
		printk("LPUART device not ready\n");
		return -ENODEV;
	}

	uart_irq_callback_user_data_set(lpuart, uart_irq_handler, NULL);

	uart_irq_rx_enable(lpuart);

	while (1) 
	{
		uart_irq_tx_enable(lpuart);
		k_sleep(K_MSEC(500));

		uart_poll_out(lpuart, 0xff);
		k_sleep(K_MSEC(100));
	}
}

static void uart_irq_handler(const struct device *dev, void *context)
{
	uint8_t buf[] = {1, 2, 3, 4, 5};

	if (uart_irq_tx_ready(dev)) 
	{
		(void)uart_fifo_fill(dev, buf, sizeof(buf));
		uart_irq_tx_disable(dev);
	}

	if (uart_irq_rx_ready(dev)) 
	{
		uint8_t buf[10];
		int len = uart_fifo_read(dev, buf, sizeof(buf));

		if (len) 
		{
			printk("read %d bytes\n", len);
		}
	}
}

I am not able to understand how do i use it ? Can you explain .. the flow of these UART API and Tx and Rx. What triggers what ?

I have used interrupt based uart.

I have my high level Application functions: Datalnit, SendData and ReceiveData in nRF52840 code to be used for UART.

uart_init i am calling inside DataInit.

What shall i write inside SendData and ReceiveData from uart code i posted.

Thanks.

[Elfving]

Hello again Deep, I hope you've had a nice weekend. 

When it comes to what to start with you could for instance base your BLE MCU on the central_uart sample. To get an understanding of the sample and UART API I would generally recommend the DevAcademy and the sample documentation, though you can of course ask here as well.

Have you gotten any further since last week?

Regards,

Elfving