Mapping System clock on GPIO

[andreaspiezia9]

Posted on November 15, 2013 at 14:06

Hi all,

I'm working with STM32F3DISCOVERY.

I'm trying to map the system clk on a GPIO to view it with an oscilloscope.

In the following datasheet 

http://www.st.com/st-web-ui/static/active/en/resource/technical/document/datasheet/DM00058181.pdf

 on page 39 I've found the signal  SWCLK-JTCK that should be the system clock, but I didn't find any information on this signal. 

Do you know this signal?

Thanks and regards

#stm32f3discovery #swclk-jtck

[Tesla DeLorean]

Posted on November 15, 2013 at 15:31

No that's a debugger clock.

To get system clocks, or fractions thereof, you need to look at MCO pins.

[andreaspiezia9]

Posted on November 18, 2013 at 14:03

Thank you Clive very much.

BTW can you tell me where the purpose of

SWCLK-JTCK

 is indicated?

Thanks and regards,

[Tesla DeLorean]

Posted on November 18, 2013 at 16:05

Like I said it's part of the debug interface, combining with SWDIO to provide a clock/data channel for the SWD interface, or part of a higher pin count JTAG interface.

It's use is optional, if you don't use the debugger they can be GPIO or other AF

[andreaspiezia9]

Posted on November 19, 2013 at 08:28

Thank you Clive