MDBT42Q NUS Example Does Not Run Correctly Using nrf Connect 2.3.0 and VS Studio Code

[Fred Eady]

I have used the Raytac MDBT42Q running NUS in past Soft Device-based projects with no problems.  Now using the new nrf Connect 2.3.0 SDK and VS Studio Code and trying to get the NUS example to run properly.  Using nrf53832 DK hardware definitions as the "board".  No custom board definitions.  Using the factory nrf52832 board definitions. Raytac device has external  32KHz crystal and is connected to nothing but 4 DK LEDs wired like the nrf52832 DK Leds. DK Button pins on the MDBT42Q are pulled high via 100k resistors. MDBT42Q LEDs and Buttons are wired just like the nrf52832 DK hardware.  I finally got the MDBT42Q to advertise and connect via BLE but data from the iPad running nrf Tool Box does not transfer.  The same code runs fine on a PCA10040 board. In addition, code only runs under Debug on the Raytac module. I've been at this for days and have attempted to use the Forum to solve the problem. Raytac UART0 prints Zephyr banner message and "Starting Nordic UART service example" to external terminal and JLink programming/debugging stuff is working correctly. Also tried this whole thing under Ubuntu and the MDBT42Q does not advertise. Out of frustration, moved to Windows where the Raytac does at least advertise and connect. Any pointers in the right direction will be greatly appreciated. Thanks in advance.

[Fred Eady]

Went back to basics.. Tried to run the blinky example.  It runs under Debug but will not start when I simply Flash the MDBT42Q.

[Hung Bui]

Hi Fred, 
You mentioned that you saw "Starting Nordic UART service example" printed out on UART when you tested with the Raytac module. Was that when it ran or when in debugging? 

Could you send the schematic of the board ? Do you do anything with the reset pin ? I assume you have a MDBT42Q 512KV2 ? Then it's pin P0.21

Another thing I think worth to try is to try flashing a simple application (blinky) in NRF5 SDK. This is to rule out any problem with nRFConnect/ Zephyr set-up you have.  

[Fred Eady]

Hi, Hung

The message only appears during debugging.  I'll include a schematic link. And, yes it is an MDBT42Q 512KV2.

I'll load up NRF5 and give that a try.              www.edtp.com/RAYTAC.pdf

[Fred Eady]

Hi, Hung

Loaded up NRF5 and flashed in various blinky/pwm examples into my home-made hardware and they all worked just fine.

I also noticed that after flashing or debugging with the new Zephyr SDK that the Raytac module hangs in limbo until I perform a tricky manual power on reset and connect operation. I literally have to power off the Raytac and start JFlash. Then, I have to power up and hit Connect in JFlash at the same instant to reestablish a connection between the Raytac and the JLink. I can then erase the Raytac part and go for another try at flashing or debugging.

[Fred Eady]

Hi, Hung

Just flashed the NUS example (ble_app_uart_pca10040_s112.hex) in NRF5 into my home-brew MDBT42Q hardware and it started right up and ran as designed.

[Hung Bui]

Hi Fred, 
It may have something to do with DCDC configuration. In nRF5 SDK the assumption is DCDC disabled by default so that it's not enabled in the code. But in Zephyr it's enabled by default :) 

There is a similar ticket here: 

 Zephyr project on a custom board wont' start up after removing debugger 

[Fred Eady]

Hi, Hung

That fixed the startup issue.  I can now connect and disconnect and run from a flash.  However, no data is being transferred.  I'll continue to work that problem and keep you in the loop.

Thanks for all of your help, Hung.  We're almost there!!