[MinnowBoard] HDMI level shifters and revision A4

[Leigh Gawne]

Hi Dave,

Thanks for the info, however in my case I must say this does not look like
the firmware issue mentioned below - I have tested this with UEFI and
coreboot/seaBIOS and this makes no difference, unlike that stated in the
ticket.

Based on the fact that there is a known issue (
https://bugzilla.yoctoproject.org/show_bug.cgi?id=7027) with the HDMI
interface being out of spec and with the testing I have done everything
points at a hardware problem. Some boards just about work, others don't at
all. EDID is all working fine. Unless the HDMI drive strengths or levels
can be adjusted by software, then I can't see how a firmware fix would
improve anything here, any thoughts?

Hence back to my earlier question about the A4 revision of the board with
proper HDMI compliant signals - is this available yet? If so I can very
easily check to see if this solves my problem.

Thanks,

Leigh
On 7 Jun 2015 18:34, "Anders, David" <david.anders at intel.com> wrote:

>  Leigh,
>
>
>
> See this bug report:
>
>
>
> https://bugzilla.yoctoproject.org/show_bug.cgi?id=7719
>
>
>
> specifically the TFP401 and TFP501 chips from TI are not working with the
> MinnowBoard Max. the issue appears to be a firmware , not hardware issue,
> and is being worked on…
>
>
>
> thanks
>
> Dave
>
>
>
> *From:* elinux-MinnowBoard [mailto:
> elinux-minnowboard-bounces at lists.elinux.org] *On Behalf Of *Leigh Gawne
> *Sent:* Sunday, June 7, 2015 2:43 AM
> *To:* MinnowBoard Development and Community Discussion
> *Subject:* Re: [MinnowBoard] HDMI level shifters and revision A4
>
>
>
> Hi Dave,
>
> I am using the TI TFP401 as the DVI decoder.
>
> I thought about spinning another revision of the board with an additional
> level shifter, but given that these are present on the A4 revision, my
> preference is just to get this revision and everything should play nice.
>
> Thanks,
>
> Leigh
>
> On 6 Jun 2015 11:21 pm, "Anders, David" <david.anders at intel.com> wrote:
>
>  Leigh,
>
>
>
> We have found that there are some DVI receiver chips that are of issue
> with the minnowboard max. which chipset are you using to covert from
> HDMI/DVI to LVDS?
>
>
>
> Dave
>
>
>
> *From:* elinux-MinnowBoard [mailto:
> elinux-minnowboard-bounces at lists.elinux.org] *On Behalf Of *Leigh Gawne
> *Sent:* Saturday, June 6, 2015 6:46 AM
> *To:* elinux-minnowboard at lists.elinux.org
> *Subject:* [MinnowBoard] HDMI level shifters and revision A4
>
>
>
> Hi guys,
>
>
>
> I have a customised daughterboard for the Minnoxboard Max which includes
> an HDMI to LVDS subsystem. During test, I have found that some boards are
> unable to drive the connected LCD display panel. Further investigation
> leads me to believe that it is the missing level shifters on the
> Minnowboard Max which mean that this is not working as expected (connecting
> other HDMI sources to the board, i.e. PC, etc. work absolutely fine.
> Inspection of the diff pair levels on a scope shows that it is definitely
> marginal).
>
>
>
> I understand that revision A4 of the board (
> https://bugzilla.yoctoproject.org/show_bug.cgi?id=7027) will include
> these level shifters. My question is whether this revision of the board is
> available yet, and if so, how I couple go about ordering a couple of them
> for test to ensure it solves my problem. I purchase around 10 boards around
> a month or so ago, and these are all revision A2.
>
>
>
> Any insights or additional information would be most helpful.
>
>
>
> Regards,
>
>
>
> Leigh
>
>
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>
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