We are bringing up a custom K22 based board. We are using P&E Multilink Rev.C with KDS 2.0 and initially we could program the K22 in SWD mode. But after a few tries, it stopped working and says "Can not enter background mode.
Unable to initialize PEDebug.
PE-ERROR: Failed to Initialize Target".
We have done all the steps mentioned by Amit/Jose in thread (https://community.freescale.com/thread/318552) but still could not make it communicate. Even JTAG mode is not working.
On analysis, we find that the RESET is occurring continuously (as we might have erased flash, causing WDRST). When we connect with debugger (or erase flash) and it is sending the JTAG to SWD pattern, we observe the pattern as in the picture. Red is SWDCLK and yellow is SWDDIO. Frequency is just 100KHz.
Only for the first 50 clocks and 79E7h pattern the SWDDIO is driven at 3.3 V whereas after that the high level is struck at 1.6V only. We tried increasing the SWDDIO pull-up to 1K, but with no effect. Is this a cause for concern?
The same debugger works fine with our custom KL25 based board with full voltage SWDDIO swing.
Looking forward for support from the community.
Thanks and Regards,