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v01d

Beginner

Date of registration: Feb 29th 2016

Posts: 16

1

Tuesday, November 1st 2016, 10:54am

[SOLVED] Cannot connect to target after watchdog reset -Vybrid

Hello,
While debugging the M4 side on VF6xx_M4, if the M4 watchdog reset happens and system restarts, I cannot connect to it with JLink unless I power cycle the board.
This is both with JLinkGDBServer and JLinkExe.

JLinkExe tells me
****** Error: Vybrid Cortex-M4 (connect): Could not power up debug port.

TotalIRLen = 4, IRPrint = 0x01
TotalIRLen = 4, IRPrint = 0x01
TotalIRLen = 4, IRPrint = 0x01
TotalIRLen = 4, IRPrint = 0x01

****** Error: Vybrid Cortex-M4 (connect): Could not power up debug port.

Cannot connect to target.
TotalIRLen = 4, IRPrint = 0x01
TotalIRLen = 4, IRPrint = 0x01
TotalIRLen = 4, IRPrint = 0x01
TotalIRLen = 4, IRPrint = 0x01

GDB server tells me

SEGGER J-Link GDB Server V6.10c Command Line Version

JLinkARM.dll V6.10c (DLL compiled Sep 28 2016 18:30:23)

-----GDB Server start settings-----
GDBInit file: none
GDB Server Listening port: 2331
SWO raw output listening port: 2332
Terminal I/O port: 2333
Accept remote connection: localhost only
Generate logfile: off
Verify download: on
Init regs on start: on
Silent mode: off
Single run mode: on
Target connection timeout: 0 ms
------J-Link related settings------
J-Link Host interface: USB
J-Link script: none
J-Link settings file: none
------Target related settings------
Target device: VF6xx_M4
Target interface: JTAG
Target interface speed: 1000kHz
Target endian: little

Connecting to J-Link...
J-Link is connected.
Firmware: J-Link V10 compiled Sep 1 2016 18:29:58
Hardware: V10.00
S/N: xxxxxxxxxxxxxx
Feature(s): RDI, FlashBP, FlashDL, JFlash, GDB
Checking target voltage...
Target voltage: 3.33 V
Listening on TCP/IP port 2331
Connecting to target...ERROR: Vybrid Cortex-M4 (connect): Could not power up debug port.

ERROR: Could not connect to target.
Target connection failed. GDBServer will be closed...Restoring target state and closing J-Link connection...
Shutting down...

The system reset pin does not help, need power cycle. Why does this happen?

This post has been edited 1 times, last edit by "v01d" (Nov 1st 2016, 10:56am)


SEGGER - Erik

Super Moderator

Date of registration: Dec 20th 2011

Posts: 387

2

Tuesday, December 6th 2016, 10:22am

Hi,

Sounds like the watchdog reset also resets the debug logic which results in J-Link loosing the connection to the device. Furthermore, it seems like after a watchdog reset occurred, the device enters a wired state where a power-on-reset is required to bring it back into a good state. We can check this again but there are some devices out there which behave similar.


Best regards
Erik

v01d1

Beginner

Date of registration: May 29th 2017

Posts: 27

3

Wednesday, June 14th 2017, 8:52am

Hi,

Sounds like the watchdog reset also resets the debug logic which results in J-Link loosing the connection to the device. Furthermore, it seems like after a watchdog reset occurred, the device enters a wired state where a power-on-reset is required to bring it back into a good state. We can check this again but there are some devices out there which behave similar.


Best regards
Erik
Thanks for answering this.
So basically Vybrid's are not debug'able with watchdogs enabled really.. Well if you hit the timeout. (which may happen as you debug.. )
:thumbdown: