Prototype Board with nRF51422 crashes on printf() statement in peripheral/Uart example.

[Akhil]

We have made a bare minimum prototype with nrf51422 QFN chip following the reference schematic for internal LDO setup in 11.5.1 section of nrf51422_PS_v3.1. It is built on a strip board with through hole components and nRF51422 on a QFN breakout board. We have omitted the external crystals and the antenna section. But added the following necessary capacitors: C7, C11, C8, C9 and C10.

It ran the Blinky example under example/peripheral successfully. When we try Uart example (without soft device) under nrfsdk/examples/peripheral, it resets at the first printf() statement. Could someone please point out what we are doing wrong here. We have created 2 prototypes and both shows this issue.

I have attached the reference schematic which we used have used. Screen Shot 2016-03-09 at 4.52.46 PM.png

Here is the source code: main.c

[MartinBL]

• Do you use the uart example completely unchanged? Otherwise do you mind posting your code?
• Which SDK are you using?
• Have you tried stepping through your code to see if you get any asserts?

[Akhil]

Hi Martin, sorry for the delay in replying. 1. Yes, I am using uart example without any modification. 2. We are using SDK 9 with SD v8. 3. I tried stepping through the code using GDB. It resets to main() when executing printf(). If I try to step inside the printf(), gdb gets confused and goes to some unknown memory location.

[MartinBL]

What are you trying to print? Do you mind sharing your code? You can submit it confidentially on our official MyPage support portal if you are not comfortable doing it here. .

[Akhil]

Hi Martin, I have attached the source code which we used. This was taken straight from the uart example included in the nrf SDK.

[MartinBL]

Hi. Maybe you are getting some kind of UART assert and end up in the uart_error_handle. Please try to put a breakpoint in the uart_error_handle and add CFLAGS += -DDEBUG to the makefile. This might stop your application instead of resetting it.