What is different between JTAG/SWD interface in FRDM-K20D50M?

[kai_liu]

I found that there are two different debugger interfaces in FRDM-K20D50M. The OpenSDA and target micros are all K20D50M family. Why does FSL decide to use JTAG for OpenSDA, and SWD for target micro? Any special reason?

[Paul_Tian]

Hi, Liu Kai

Because Cortex-M0+ does not support JTAG debug, so Kinetis L series use SWD debug interface. But if you have J-Link on your hand, you can use top half interface for SWD debug. Thanks.

Hope my reply can help you.

Best Regards

Paul

[jeremyzhou]

Hi Kai,

In fact, I also don't know the exactly reason and I've nout found the special reason for these desgins in any documents.

However I think it's not hard to speculate. L series Kinetis only support SWD which make it can't support other debug interfaces except SWD.

K series Kinetis can both support JTAG and SWD, so choose JTAG is reasonable.

Wish can help.

Best regards,

Ping