How to close UART to save power for nRF52810

RE: How to close UART to save power for nRF52810

MartinBL — Thu, 25 Jan 2018 12:43:13 GMT

Is it stuck in app_error_fault_handler()? Have you debugged and checked the error code, line number, and file name?

RE: How to close UART to save power for nRF52810

Alice — Thu, 25 Jan 2018 01:41:26 GMT

For our application, if the MCU want to send data to the 52810 module via uart, it will keep P0.31 low until finishing sending data then let the P0.31 high to save power.

There's no problem that just pushed and released the button much time, because the uart still could output 0x55 0x66 in the handle_uart_sta function.

But the problem is, once the uart has received data,for example,use UART terminal on the PC to send data to nRF52810, it will get stuck and there's no any reaction push and releas the button at this time.

RE: How to close UART to save power for nRF52810

MartinBL — Wed, 24 Jan 2018 11:35:57 GMT

I'm still not sure what you are trying to achieve here, but it seems like when:

you press the button bsp_event_handler() is called with event BSP_EVENT_UART_WORK
uart_status is set to 2
After that handle_uart_sta() is called from main context
Since uart_status = 2 NRF_UARTE0->ENABLE is set to 8 (enabled).
Average current consumptions is ~750uA

As long as you keep the button pressed the UART still works. When you release the button though:

bsp_event_handler() is called again with event BSP_EVENT_UART_SLEEP
uart_status is set to 1
After that handle_uart_sta() is called from main context
Since uart_status = 1 NRF_UARTE0->ENABLE is set to 0 (disabled).
Average current consumptions goes down to ~190uA

So i.e. after you have pushed and released the button the UART is disabled.

Is this your problem?

RE: How to close UART to save power for nRF52810

Alice — Tue, 23 Jan 2018 15:09:55 GMT

You could flash it to nRF52810 then it would runs and it would print "Application start" through UART. After that, you could give a high or low level by hand to P0.31. This should work fine. If you use UART terminal on the PC to send data to nRF52810, then give a high or low level by hand, you could see the problem.

RE: How to close UART to save power for nRF52810

MartinBL — Tue, 23 Jan 2018 14:54:08 GMT

Can you give me a step-by-step instruction showing what I should do to reproduce your problem?

RE: How to close UART to save power for nRF52810

Alice — Sat, 20 Jan 2018 04:34:22 GMT

I have declared uart_status as 'volatile'. Also I use NRF_UARTE0->ENABLE = 8; and NRF_UARTE0->ENABLE = 0; to instead of app_uart_open() and app_uart_close(). I could see the current and it's 2.6uA when disable UART while it's about 650uA when enabled UART. UART could send data after it's enabled. But once use PC to send the UART more than two times, it would get stuck and stop running at the app_error_fault_handler function. That's to say, UART couldn't receive any data after enabled. Could you help me have a test on the ble_app_uart example? Thanks very much.

This link text is my complete project. I use P0.31 to generate the high or low level to enabled or disable UART.

RE: How to close UART to save power for nRF52810

MartinBL — Fri, 19 Jan 2018 13:41:05 GMT

It seems like you have done what I was thinking.

Can you try to declare uart_status as 'volatile'?

Have you tried debugging by the way? Do you know where things stop?

RE: How to close UART to save power for nRF52810

Alice — Fri, 19 Jan 2018 06:43:20 GMT

Hi Martin, I'm not sure I have got what you mean. Firstly, I have increase the interrupt priority of the UART to APP_IRQ_PRIORITY_HIGH. Then I have a global variable uart_status. I set uart_status=1 in the BSP_EVENT_UART_SLEEP event while uart_status=2 in the BSP_EVENT_UART_WORk event. The two dunction app_uart_close() and app_uart_open() would be called in the main context and NRF_LOG_FLUSH() also would be called before enable or disable the UART as follow:

static uint8_t uart_status = 0;
void handle_uart_sta(void){
	switch(uart_status)
	{
		case 1:
						uart_status = 0;
						NRF_LOG_FLUSH();
						app_uart_close();
		break;
		case 2:
						uart_status = 0;
						NRF_LOG_FLUSH();							
		        app_uart_open();
		break;				}		}

In the main context:

    for (;;){
    UNUSED_RETURN_VALUE(NRF_LOG_PROCESS());
    power_manage();
    handle_uart_sta();
   }

However, the problem have not been solved.

RE: How to close UART to save power for nRF52810

MartinBL — Thu, 18 Jan 2018 12:18:46 GMT

Are you using the logger module with UART as backend and without deferred logging? It could be a problem related to my comment from January 11th here. nrf_drv_uart_uninit () is trying to print messages to the logger module, and if you do this over UART I figure that you might get stuck if you call it from the interrupt context of the bsp_event_handler. app_uart_open() will also end up in an error handler if you try to call it more than once without successfully calling nrf_drv_uart_uninit() in between. It could help to either:

Increase the interrupt priority of the UART to e.g. APP_IRQ_PRIORITY_HIGH.
Move your calls to app_uart_close() and app_uart_open() into your maint context.
Use deferred logging and flush the message with NRF_LOG_FLUSH() in your main context. Logger documentation.

RE: How to close UART to save power for nRF52810

Alice — Thu, 18 Jan 2018 11:56:14 GMT

Yes, I have define BSP_EVENT_UART_SLEEP and BSP_EVENT_UART_WORK in the bsp_event_t. It also could generate the event and run to the bsp_event_handler.

RE: How to close UART to save power for nRF52810

Alice — Thu, 18 Jan 2018 11:51:07 GMT

nrf_uart_disable will be called in the nrf_drv_uart_uninit function.

RE: How to close UART to save power for nRF52810

Andre — Thu, 18 Jan 2018 09:40:03 GMT

Try adding a call to nrf_uart_disable

RE: How to close UART to save power for nRF52810

Hieu — Thu, 18 Jan 2018 08:26:34 GMT

Did you define BSP_EVENT_UART_SLEEP and BSP_EVENT_UART_WORK somewhere? I don't think such events exist in unmodified BSP module.