Common JTAG Issues

Hart unexpectedly reset

Error message:

> openocd -f .\bearlyml.cfg
Open On-Chip Debugger 0.11.0-rc1+dev (SiFive OpenOCD 0.10.0-2020.12.1)
Licensed under GNU GPL v2
For bug reports:
        https://github.com/sifive/freedom-tools/issues
Info: clock speed 100 kHz
Info: JTAG tap: riscv.cpu tap/device found: 0x00000001 (mfg: 0x000 (<invalid>), part: 0x0000, ver: 0x0)
Info: datacount=2 progbufsize=16
Info: Hart 0 unexpectedly reset!
Info: Hart 0 unexpectedly reset!
Info: Hart 0 unexpectedly reset!
Info: Hart 0 unexpectedly reset!
Info: Hart 0 unexpectedly reset!
Info: Hart 0 unexpectedly reset!
Info: Hart 0 unexpectedly reset!
Info: Hart 0 unexpectedly reset!
Info: Hart 0 unexpectedly reset!

This issue happened when testing BearlyML 22 using jumper wire harness on the breakout board. No solution was found. However, the issue disappeared when we moved to a more complete demo board, so we suspect this might be due to some signal integrity issue.

Solution:

check harness

Unable to halt hart

error message:

> openocd -f .\bearlyml.cfg
Open On-Chip Debugger 0.11.0-rc1+dev (SiFive OpenOCD 0.10.0-2020.12.1)
Licensed under GNU GPL v2
For bug reports:
        https://github.com/sifive/freedom-tools/issues
Info: clock speed 100 kHz
Info: JTAG tap: riscv.cpu tap/device found: 0x00000001 (mfg: 0x000 (<invalid>), part: 0x0000, ver: 0x0)
Info: datacount=2 progbufsize=16
Error: unable to halt hart 0
Error:   dmcontrol=0x80010001
Error:   dmstatus =0x00030ca2
Error: Fatal: Hart 0 failed to halt during examine()
Warn: target riscv.cpu0 examination failed     

solution:

check if core is bring out of reset.

check if core is powered

check if system clock is supplied

JTAG Scan chain all ones

Device is not connected to the debugger. Check connection to the DUT device.

(base) tk@TK-Avenue-Ubuntu:~/Desktop/HAL/jtag$ openocd -f osciarty.cfg 
Open On-Chip Debugger 0.11.0-rc1+dev (SiFive OpenOCD 0.10.0-2020.12.1)
Licensed under GNU GPL v2
For bug reports:
        https://github.com/sifive/freedom-tools/issues
Info : clock speed 2000 kHz
Error: JTAG scan chain interrogation failed: all ones
Error: Check JTAG interface, timings, target power, etc.
Error: Trying to use configured scan chain anyway...
Error: riscv.cpu: IR capture error; 
Warn : Bypassing JTAG setup events due to errors
Error: Unsupported DTM version: 15
Warn : target riscv.cpu examination failed
Info : starting gdb server for riscv.cpu on 3333
Info : Listening on port 3333 for gdb connections
Error: Target not examined yet

Error: Unsupported DTM version: 15