J-Link-OB Not Working on sama5d27-som1-ek

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arshadaleem
Posts: 1
Joined: Mon Sep 16, 2019 2:27 pm

J-Link-OB Not Working on sama5d27-som1-ek

Mon Sep 16, 2019 2:54 pm

Hi there!

I am running Ubuntu 16.04 at my host. and I have built an image for my sama5d27-som1-ek board while using meta-atmel layer.
Flashed the image and connected the J10 port with my PC for serial connection. As the documentation indicated that JLink OB is also integrated on the same port J10, that's why I expect to connect JLink and establish a gdb server connection with it.

While my board is in U-Boot prompt, I try to establish gdb server connection:

Code: Select all

$ JLinkGDBServer -singlerun -nogui -if JTAG -port 2331 -select usb=483084593 -device ATSAMA5D27 -noir
SEGGER J-Link GDB Server V6.46k Command Line Version

JLinkARM.dll V6.46k (DLL compiled Jul 22 2019 10:54:31)

Command line: -singlerun -nogui -if JTAG -port 2331 -select usb=483084593 -device ATSAMA5D27 -noir
-----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:      yes
Generate logfile:              off
Verify download:               off
Init regs on start:            off
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:                 ATSAMA5D27
Target interface:              JTAG
Target interface speed:        4000kHz
Target endian:                 little

Connecting to J-Link...
J-Link is connected.
Firmware: J-Link OB-SAM3U128 V3 compiled Jan  7 2019 14:06:26
Hardware: V3.00
S/N: 483084593
Checking target voltage...
Target voltage: 3.30 V
Listening on TCP/IP port 2331
Connecting to target...ERROR: Could not connect to target.
Target connection failed. GDBServer will be closed...Restoring target state and closing J-Link connection...
Shutting down...
Could not connect to target.
Please check power, connection and settings.
At the same time, my target gets rest!

As a test, I unmounted my SD card containing the U-Boot and the rest of image, and again try to connect the gdb server, and this time connection establishes and no error is displayed:

Code: Select all

JLinkGDBServer -singlerun -nogui -if JTAG -port 2331 -select usb=483084593 -device ATSAMA5D27 -noir
SEGGER J-Link GDB Server V6.46k Command Line Version

JLinkARM.dll V6.46k (DLL compiled Jul 22 2019 10:54:31)

Command line: -singlerun -nogui -if JTAG -port 2331 -select usb=483084593 -device ATSAMA5D27 -noir
-----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:      yes
Generate logfile:              off
Verify download:               off
Init regs on start:            off
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:                 ATSAMA5D27
Target interface:              JTAG
Target interface speed:        4000kHz
Target endian:                 little

Connecting to J-Link...
J-Link is connected.
Firmware: J-Link OB-SAM3U128 V3 compiled Jan  7 2019 14:06:26
Hardware: V3.00
S/N: 483084593
Checking target voltage...
Target voltage: 3.30 V
Listening on TCP/IP port 2331
Connecting to target...
J-Link found 1 JTAG device, Total IRLen = 4
JTAG ID: 0x5BA00477 (Cortex-A5)
Connected to target
Waiting for GDB connection...
  • Moreover, applying jumper at J7 and connecting external JLink to the board at J11 port, portrays the same behavior.
  • Secondly, trying to establish the gdbserver connection after the linux image is up, causes same behavior as well.
I had opened an inquiry at Segger support website because the JLink OB device is supported by them. But as the JLink device is "behaving as expected" on baremetal, that's why they indicated that something from U-Boot or Kernel is disabling the JTAG clocks or re-configuring it's pins.

What are the suspects for this behavior? Any pointer to help my investigation will be appreciated.

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