JTAG maximum trace length

Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

cross mob
MiBr_1434631
Level 1
Level 1
First like received

Is there a maximum trace length for the JTAG wires when connected to a PSoC 5LP?

I've done some research and I found some sites that say the limit is 3" and other sites that say there's no practical limit.

0 Likes
1 Solution

This sounds like a good candidate for a bootloader.  So you can test/debug via JTAG in the lab and then deploy to the field using something like a UART.

Edit: cleaned up the grammar, that's what I get for replying on mobile.

View solution in original post

0 Likes
3 Replies
LinglingG_46
Moderator
Moderator
Moderator
500 solutions authored 1000 replies posted 10 questions asked

I think the JTAG wires don't limit the length, but should limit the parasitic capacitance.

You should guarantee it can meet the programming timing spec.

Can you explain why you have such questions? Does your system have a limit use?

0 Likes

In order to keep the traces short I tend to put the jtag connector right next to the PSoC but when the board gets installed in the field the connector and the processor end up hidden underneath a bundle of cables. The only easily accessible space is a good 4.5" away from where the PSoC is located.

0 Likes

This sounds like a good candidate for a bootloader.  So you can test/debug via JTAG in the lab and then deploy to the field using something like a UART.

Edit: cleaned up the grammar, that's what I get for replying on mobile.

0 Likes