Hello,
I have previously been working with a custom board with a Kinetis MK20 (MK20DX256VLH7) without problems.
Now I have designed a new board for the MK22FN1M0AVMC12 following the schematic from the Tower Kit TWR-K21F120M.
I am currently trying to program the uC using Kinetis Design Studio and the PE Micro Multilink Universal through SWD, (which worked fine in my previous design) without success, and I am getting the error: "GDB server was not able to establish a connection to the target processor", attached a screenshot of the errors I get.
Attached I also include the main conections of the uC in the design, as well as the SWD interface. At first I thought that the problem was that I had a pullup resistor in SWD_CLK, and I read somewhere it shouldnt have this resistor, so I removed it, but still couldnt connect to the uC.
I have tried building a project from scratch and using the SDK for this uC downloaded from the SDK builder at mcuxpresso.nxp.com, attempting to load an empty project without success.
Could you give me hints on where should I look for possible errors? The 3.3V of the board seems correct, and the PE micro also receives this power. Should I make any modifications to the programming in KDS, or should some hardware items be modified to try again?
Thank you in advance for your attention.
Hi,
VBAT is not likely to be the problem. TWR-K22 connects MCU_PWR with VBAT.
RTC_wakeup_b pin is a open drain output ping. It should be no influence to system.
Vref_OUT is contorled by VREFV1 register. If it is not set, output should be zero.
I think EZP_CS/NMI should be pullup. Because the default value of FPOT is 0xff. It selects the EZP_CS function of the pin. If it is low during power on, device will enter EZPort mode. Then SWD will not work.
Regards
Jing