Hello!
Could you please advise if the following schematic is recommended for SWD / JTAG adapted for Kinetis MCUs (MKM33):
HardwareDebugConnections - ** Code Red Support Site **
Or it's better to use another one?
Is it critical to use pull-up and pull-down resistors for SWCLK and SWDIO lines? May the adapter work without them?
Thanks,
Alexey
Hi Alexey,
SWD_CLK is pulled down internally, and SWD_IO is pulled up internally. (You can get this information from MKMXXZXXACXX5RM.)
It isn't critical to use pull-up and pull-down resistors for SWCLK and SWDIO lines. The adapter may work without them.
The external pull-up shown in some diagrams is for potentially noisy environments, and should be on the order of 10kΩ.
From the Kinetis L Quick Reference User Guide (KLQRUG):
The RESET_b pin should have a 100 nF capacitor close to the MCU for transient protection. It has a weak internal
pullup, but an external 4.7 kΩ to 10 kΩ pullup is recommended.(From the Kinetis L Quick Reference User Guide KLQRUG)
Best Regards,
Robin
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Hi Alexey!
As for SWD you no need to add any resistors. At least it worked for me for kv10,mk10,mk22,kv30,kv31,kl27 MCUs. And dont mess with reset-you need reset_b pin to trace to reset of JTAG.
Best regards and "yda4i",
Alexey.