Dahlia Erratum #9 HAR-8814

Technical Support
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1

Dahlia Carrier Board V1.1A
Verdin iMX8MP Q 4GB IT
Toradex Linux Multimedia Image

We have applied HAR-8814 by replacing the 5 resistors as indicated here: Dahlia Carrier Board | Toradex Developer Center and also in the erratum PDF: https://docs.toradex.com/107810-dahlia-carrier-board-errata.pdf
but the board still suffers from a Power-Down when the DBG connector is connected to a laptop.
Did anyone else apply this specific fix to a Dahlia 1.1A board?

2

Could you pleas specify are you talking about X18 Debug connector? When exactly PowrDown happened - when you plug Cable into X18 (other end of cable is disconnected)?

  • When you plug cable into X18 while other end cable of already connected to PC?
  • When you run terminal program on your PC (cable already fully connected)?
3

Yes, I am talking about X18 Debug connector.
Dahlia is running the multimedia image, no cable on X18.
I can connect a cable to X18 - no problem.
I connect the other end of the cable to a laptop - power down.
We do not run a terminal program.
There is no problem when the cable connection from X18 to the laptop is set up before Power-On of the Dahlia.

4

Could you insert cable first and then power up a Dahlia board?

5

When the cable is inserted first and then Dahlia is powered up there is no problem.

I am talking about your proposed “alternative solution” for the HAR-8814 (replacing 5 resistors with other values). This alternative solution seems not to work in our case, behaviour is identical to not replacing the resistors.

  • maybe replacing 5 resistors is not the whole story, are there other modifications necessary to fix this bug on a Dahlia V1.1A Version?
  • maybe the resistor numbers are wrong or incomplete (R102, R109, R115, R120, and R245)?
  • maybe the proposed new value of 1 MOhm is incorrect?
6

Hello zorro,

the mentioned resistors are the right ones and the value is the one we recommend.
We have to replicate that here first with a test.

Best Regards,
Matthias

7

Hello zorro,

we tested this with a board the proposed solution and we did not see the reset.

Best Regards,

Matthias Gohlke