ble_app_uart_c problem using a WT51822-S4AT board

[samuel.zetterlund]

Hi,

 

I have a couple of WT51822-S4AT boards I would like to use to send data from a PC to one board via UART and then pass the data to a microcontroller connected to the other board via its UART.

So: PC --> n51822 --> n51822 --> microcontroller.

 

I managed to get the ble_app_uart peripheral example working by changing the RX/TX pins and changing the flash layout and compiling for BOARD_WT51822 instead of for example BOARD_PCA10028.

 

Using the nRF toolbox app on my phone I can send data to that peripheral board.

 

But, now I would like to use the other board as a central and I can't seem to get it working. I get stuck in the sd_ble_gap_scan_start function which returns the error code 0x00000007 and then the device is reset.

Do you have any clue why I'm getting this error?

 

 

Thanks in advance,

Samuel

[samuel.zetterlund]

I can add that the working peripheral example has the following clock settings:

In main header

#if MODULE_WT
#undef NRF_CLOCK_LFCLKSRC
#define NRF_CLOCK_LFCLKSRC {.source = NRF_CLOCK_LF_SRC_SYNTH, \
.rc_ctiv = 0, \
.rc_temp_ctiv = 0, \
.xtal_accuracy = NRF_CLOCK_LF_XTAL_ACCURACY_20_PPM}
#endif

In ble_stack_init:

nrf_clock_lf_cfg_t clock_lf_cfg = NRF_CLOCK_LFCLKSRC;

// Initialize SoftDevice.
SOFTDEVICE_HANDLER_INIT(&clock_lf_cfg, NULL);

The central example looks a bit different. In ble_stack_init, the SDK example doesn't pass a struct to SOFTDEVICE_HANDLER but only a defined value as:

SOFTDEVICE_HANDLER_INIT(NRF_CLOCK_LFCLKSRC_SYNTH_250_PPM, NULL);

When setting the clock source to NRF_CLOCK_LFCLKSRC_SYNTH_250_PPM, I get the error code 7 as I wrote earlier. 

However, when setting the clock source to NRF_CLOCK_LFCLKSRC_XTAL_20_PPM, I get the error code 0x1000.

[MartinBL]

Hi, 

Sorry for the late response. 

Have you made any progress? 

If not, what SDK and Softdevice versions are you using? And are you using an example to get started? 

I was not able to find a good datasheet for your module, but if it is this one, you can see that it doesn't have any external LF Crystal, so using NRF_CLOCK_LFCLKSRC_XTAL_20_PPM is out of the question. Using NRF_CLOCK_LFCLKSRC_SYNTH_250_PPM should always work though. 

[samuel.zetterlund]

Hi again,

Now it's my time to apologize for the late answer. I had to stall this issue for quite some time and focus on other things with this project and now when I returned to this issue, the problem I faced earlier seems to be gone.

I didn't change anything to the code (or at least I don't think so) and now the central scans for peripherals and it connects to the peripheral. However, I can't seem to send anything from the central or peripheral. See this ticket:

devzone.nordicsemi.com/.../wt51822-s4at-uart-problem-board-can-receive-data-but-not-send

[MartinBL]

Ok, so can we consider this case as closed?

I'll be traveling the rest of the week, but someone else will handle your other ticket. 

Martin

[Sepehr1989]

Thank you so much.

It was my problem too, but solved