SWO in nRF51422 using ST LINK V2 DEBUGGER

[HK]

Hello, 

I am developing an application using the nRF51422.

For flashing and debugging the nRF, I use a ST-Link V2 debugger which uses SWD. The IDE I use is uVision. 

I understand that while debugging on chip, I can use the SWDIO and SWCLK lines of nRF. 

However, I want to use 'printf' style debugging. For this I guess we require SWO pin on the nRF which is not present on it.

So, is there a way we can make 'printf' do it's job without SWO on the nRF?

What is the difference between SWDIO and SWO ? 

I hope you will answer asap.

Thanks & Regards

[Nguyen Hoan Hoang]

You can enable Semihosting for that.  No SWO needed.  See this blog http://embeddedsoftdev.blogspot.com/p/idap-link.html at the bottom in the Semihosting section.  It show how to enable it in the code and GCC compile flag. 

[HK]

Hello Nguyen,

Greetings. 

Thanks for the reply. 

I have 2 questions.

1. Does Semihosting work with KEIL uVision?

2. Will the ST LINK V2 work? Or I have to get another debug donggle?

Thanks & Regards. 

[Nguyen Hoan Hoang]

1. I haven't worked with Keil too much but the Semihosting code is part of the newlib (clib) library.  Keil also uses it so I guess it should work.  

2. You can check in the property setting for debugger to see if ST-Link is listed in the selection.  If it is listed then it should work.  I work mainly on Mac OSX with Eclipse/GCC/OpenOCD.