I'm using a Kwikstik as my debugger on my custom K53DN512 board. I have been debugging successfuly for several weeks, but yesterday I somehow locked a chip, and today, I am getting a message that J-Link can no longer halt the device after reset. Has anybody seen this? I have tried switching between JTAG and SWD with no success. Please help! Here's the output from the J-Link Commander software when issuing a reset. SWD results are similar:
SEGGER J-Link Commander V4.40b ('?' for help)
Compiled Dec 22 2011 10:55:05
DLL version V4.40b, compiled Dec 22 2011 10:54:45
Firmware: J-Link Lite-FSL V1 compiled Jan 31 2011 11:00:51
Hardware: V1.00
S/N: 430110131
VTarget = 3.435V
Info: TotalIRLen = 4, IRPrint = 0x01
Info: Found Cortex-M4 r0p0, Little endian.
Info: TPIU fitted.
Info: ETM fitted.
Info: ETB present.
Info: CSTF present.
Info: FPUnit: 6 code (BP) slots and 2 literal slots
Found 1 JTAG device, Total IRLen = 4:
#0 Id: 0x4BA00477, IRLen: 04, IRPrint: 0x1, CoreSight JTAG-DP (ARM)
Cortex-M4 identified.
JTAG speed: 100 kHz
J-Link>r
Reset delay: 0 ms
Reset type NORMAL: Resets core & peripherals via SYSRESETREQ & VECTRESET bit.
Info: TotalIRLen = 4, IRPrint = 0x01
Info: Found Cortex-M4 r0p0, Little endian.
Info: TPIU fitted.
Info: ETM fitted.
Info: ETB present.
Info: CSTF present.
Info: FPUnit: 6 code (BP) slots and 2 literal slots
Info: Found Cortex-M4 r0p0, Little endian.
Info: TPIU fitted.
Info: ETM fitted.
Info: ETB present.
Info: CSTF present.
Info: FPUnit: 6 code (BP) slots and 2 literal slots
WARNING: S_RESET_ST not cleared
WARNING: CPU did not halt after reset.
Info: Found Cortex-M4 r0p0, Little endian.
Info: TPIU fitted.
Info: ETM fitted.
Info: ETB present.
Info: CSTF present.
Info: FPUnit: 6 code (BP) slots and 2 literal slots
WARNING: CPU could not be halted
Info: Core did not halt after reset, trying to disable WDT.
WARNING: CPU did not halt after reset.
Info: Found Cortex-M4 r0p0, Little endian.
Info: TPIU fitted.
Info: ETM fitted.
Info: ETB present.
Info: CSTF present.
Info: FPUnit: 6 code (BP) slots and 2 literal slots
WARNING: CPU could not be halted
WARNING: CPU did not halt after reset.
Info: Found Cortex-M4 r0p0, Little endian.
Info: TPIU fitted.
Info: ETM fitted.
Info: ETB present.
Info: CSTF present.
Info: FPUnit: 6 code (BP) slots and 2 literal slots
WARNING: CPU could not be halted
WARNING: S_RESET_ST not cleared
Solved! Go to Solution.
I believe that we figured out the issue. The Kwikstik has a 1k resistor (R113) between the MCU reset pin on the JTAG connector and the Kwikstik's Kinetis 3.3V supply. It appears that when the Kwikstik is used as a debugger for an external MCU, this 1k resistor acts as a pull-down, biasing the reset line low. It looks like sometimes the line would reset successfully, and sometimes it wouldn't. Pulling R113 seems to fix the issue.
I believe that we figured out the issue. The Kwikstik has a 1k resistor (R113) between the MCU reset pin on the JTAG connector and the Kwikstik's Kinetis 3.3V supply. It appears that when the Kwikstik is used as a debugger for an external MCU, this 1k resistor acts as a pull-down, biasing the reset line low. It looks like sometimes the line would reset successfully, and sometimes it wouldn't. Pulling R113 seems to fix the issue.