JTrace for XMC4700

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User20222
Level 1
Level 1
First solution authored
Hello,

I am currently setting up ETM Trace for the XMC4700.

Port 7-8 is currently configured for the TRACECLCK pin (see https://www.segger.com/products/debug-probes/j-trace/models/j-trace/)
Port 8-1 is for TRACEDATA[0]

The issue I'm running into is trace stops working as soon as this function is called:
XMC_SCU_CLOCK_SetSystemClockSource(XMC_SCU_CLOCK_SYSCLKSRC_PLL);   


I'm not sure how to change the TRACECLCK source to the system pll, if that's even possible. Or, am I configuring the trace settings incorrectly?

Thanks!
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1 Solution
User20222
Level 1
Level 1
First solution authored
The issue seems to be clock speed and pin drive strenghts.
That is why previously, as soon as this function is called the trace stops working:
XMC_SCU_CLOCK_SetSystemClockSource(XMC_SCU_CLOCK_SYSCLKSRC_PLL);


Our esteemed colleague pointed us to an errata in the datasheet that mentions a couple ports have some drive strength values that cannot be written via software.
XMC4700_XMC4800_AA-ES-v01_04-EN page 41 and 42

The workaround for the ETM is to run the CPU at a slower clock speed. In our case, 72MHz allowed us to get trace working again.


5175.attach

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LinglingG_46
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500 solutions authored 1000 replies posted 10 questions asked
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User20222
Level 1
Level 1
First solution authored
The issue seems to be clock speed and pin drive strenghts.
That is why previously, as soon as this function is called the trace stops working:
XMC_SCU_CLOCK_SetSystemClockSource(XMC_SCU_CLOCK_SYSCLKSRC_PLL);


Our esteemed colleague pointed us to an errata in the datasheet that mentions a couple ports have some drive strength values that cannot be written via software.
XMC4700_XMC4800_AA-ES-v01_04-EN page 41 and 42

The workaround for the ETM is to run the CPU at a slower clock speed. In our case, 72MHz allowed us to get trace working again.


5175.attach
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