[SOLVED] JLink Daisychain

bharaths · Apr 27th 2016, 8:04pm

I am trying to daisy chain three boards that have ARM ATMEL SAM4E16C chips on them. I have made a custom harness as per the guidelines in UM08001. So the system interconnections look as follows : Linux PC -> USB -> J Link Pro -> JTAG Connector Harness -> Daisy Chained boards. The aim is to program/communicate the three boards using a single JLink Pro. I have some queries to get this working:
- Where can i enter the configuration details (IR Len, Position)
- I do have MAC and IPs assigned to each of the boards. Will this help ?
- I have also tried using Windows PC to do the same. But failed

Please let me know if further information is required.

SEGGER - Niklas · Apr 29th 2016, 11:06am

Hi ,

I have made a custom harness as per the guidelines in UM08001

Could you tell me to which section of the manual you are referring to?

- Where can i enter the configuration details (IR Len, Position)

I assume you are using J-Link Commander (JLinkExe).
It is possible to pass -JTAGConf <IRPre>,<DRPre> as a command line parameter.

Best regards,
Niklas

bharaths · Apr 29th 2016, 5:19pm

HI Niklas,

I am referring to the Section 5.3 of the manual for the JTAG scan chain.
I am currently using a ubuntu machine.

I tried running the JLinkExe with the command line paramater.
But I am yet to ascertain if that is working.

Thanks
Bharath

bharaths · May 12th 2016, 9:59pm

Hi Niklas,

I have some more queries on the JTAG daisychain

a) I have created a daisychain harness as per the diagram in page 178. The ground pins (3,5) and VTref(1) are not connected. Do I need to connect them (Tried doing it, but did not work)
b) Is there a way to communicate to a specific device in the daisychain ? Any JLinkExe command line options or through settings or via script file JlinkScriptFile. (in Linux)
c) Does the JTAG configuration automatically switch over to a SWD mode ? When i powered on the daisy chain with 3 devices, it detected one device in SWD mode.

Please let me know of additional input is required.
Thanks
Bharath

SEGGER - Niklas · May 13th 2016, 9:21am

Hi Bharath,

a) They have to be connected.

From the questions b) and c) I assume you are using an old version of the J-Link software.
The current J-Link software package is available free of charge here .

A specific device in the chain can be chosen by passing "-JTAGConf <IRPre>,<DRPre>" as a command line parameter (works only with current versions!)
As an alternative, "-jtagconf -1,-1" can be passed, then J-Link Commander will try to connect to the first device found in the chain that matches the device or core specified (specifying a device or at least a core is mandatory with current versions(5.10 or later) of the J-Link software)

Best regards,
Niklas

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