Advice for HDMI Users

[PikWik]

Confirmed — the CEC-Less cable cures the ARC / CEC problems.

So my setup now consists of the CEC-Less cable plugged straight into MiSTer, then plugged into the CableMatters repeater’s “input”, then an HDMI cable connected from the repeater’s “output” into one of my soundbar’s inputs.

thank you for your continued efforts with this.

i ordered the CEC-less cable, and a monoprice HDMI repeater for my MiSTer setup.
im hoping this will fix an issue with my HDTV (SAMSUNG Q70R) where the bottom of the screen will show random tearing in "low lag" mode, and strange graphic glitches on the lower part of the screen every once in a while in vsync_adjust=2.

when i set the vsync_adjust to 1 (match core frequency) the HDTV/MiSTer is butter smooth with no issues, UNLESS i switch from the MiSTer HDMI input to a different input (HDMI input 1 to HDMI input 2) while a game is running.
if i do that, i have to reset the MiSTer core and then its butter smooth again.
noting, i have played for long stretches and the Q70R in vsync_adjust=1 (match core frequency) is perfect.

and if the repeater doesnt fix those random issues, it will be nice to know the HDMI signal is as clean as possible and wont interfere with ARC or a soundbar down the road

[nexusmtz]

Confirmed — the CEC-Less cable cures the ARC / CEC problems.

Here's an inexpensive product that also solves the CEC problem:
Ensigear Remote Controlled HDMI 2.0 IR Adapter. Ignoring the misleading title, they're adapters that are intended to pass IR signals down pin 13, but if you don't plug an IR cable in, then nothing gets connected to pin 13. Put one on the DE10 end of the HDMI cable, set it to IR, and watch ARC work again. Currently, they're 2 for $9.99. (They come in pairs since you'd need two for their intended purpose.)

I know you're already working with the CEC-Less cable, but others might be looking for an alternative.

[yossariano]

I just registered with these forums to say a big thank you to everybody in this topic. I was getting ready to return my fancy new TV speakers because they kept dropping from the HDMI ARC connection and the TV would go back to the onboard speakers. I didn't correlate it with the MiSTer at all- but sure enough, I don't see any of that behavior while the MiSTer is disconnected from HDMI. I've ordered the Lindy CEC-less adapter and I'm hoping that fixes things to good. I appreciate everybody who looked into this.

[Alkadian]

Confirmed — the CEC-Less cable cures the ARC / CEC problems.

Here's an inexpensive product that also solves the CEC problem:
Ensigear Remote Controlled HDMI 2.0 IR Adapter. Ignoring the misleading title, they're adapters that are intended to pass IR signals down pin 13, but if you don't plug an IR cable in, then nothing gets connected to pin 13. Put one on the DE10 end of the HDMI cable, set it to IR, and watch ARC work again. Currently, they're 2 for $9.99. (They come in pairs since you'd need two for their intended purpose.)

I know you're already working with the CEC-Less cable, but others might be looking for an alternative.

First of all, many thanks to all of you that shared this important information!

Am I right in saying that one of these IR over HDMI adpaters will not require an additional CEC-less cable?

Thanks!

[pjtonge]

I reckon this is caused by an ESD protection device called U34 on the bottom of the PCB. There is a diode inside this device between CEC and the 5V rail, so when power is disconnected, the diode pulls the CEC line low and stops it working. I cut the connection to pin 1 (see attached picture) and my ARC issues went away. I don't think the ESD protection is needed since pin 13 doesn't go anywhere else on the DE10-Nano.

[Insert Disk Two]

Ideally we get an option in cores to adjust speed to run at exactly 60hz. I had a similar issue with Neogeo core but a kind soul has modified the core and now it runs perfectly smooth on any display.

Analogue consoles also come with this option out of the box, so it can be done

[LXZ]

Ideally we get an option in cores to adjust speed to run at exactly 60hz. I had a similar issue with Neogeo core but a kind soul has modified the core and now it runs perfectly smooth on any display.

Analogue consoles also come with this option out of the box, so it can be done

Either you are replying to the wrong topic or I don't see the connection between 60hz and HDMI pin 13...

[Insert Disk Two]

Sorry I was answering Aberu:

"
I lucked out with my 70" Sharp Aquos TV in my main room, as it seems to support a range of vsync frequencies centered around both 50Hz and 60Hz. But if I feed anything other than an exact 60Hz signal to my newer-model SAMSUNG in my guest bedroom, it will achieve sync and display the image, but the image will exhibit bizarre stuttering behavior (every so often, it will momentarily show a frame that is from 2-3 frames ago, such that any smooth motion appears to suddenly lurch backward for a frame). "

[keith.f.kelly]

NEW INFO: There is STILL something electrically weird going on with MiSTer's HDMI port. Even using the CEC-less cable and the CableMatters booster, if the MiSTer is plugged into my new 4K Samsung Q90T television, then the TV is unable to correctly detect that it is connected to an eARC AV receiver on a different input. Something about the MiSTer electrically messes with the eARC communication mechanism; possible some other pin that is only used for eARC?

At this point, I'm thinking the only way to truly electrically isolate may be to resort to a short fiber optic HDMI cable. They aren't cheap, but in theory they should truly electrically disconnect all the pins from one end to the other.

[keith.f.kelly]

I reckon this is caused by an ESD protection device called U34 on the bottom of the PCB. There is a diode inside this device between CEC and the 5V rail, so when power is disconnected, the diode pulls the CEC line low and stops it working. I cut the connection to pin 1 (see attached picture) and my ARC issues went away. I don't think the ESD protection is needed since pin 13 doesn't go anywhere else on the DE10-Nano.

Any chance this fix might also apply to HDMI pins 14 and 19, which are the "ethernet over HDMI" pins responsible for eARC? Because even with the CEC pin (13) removed from the equation, my MiSTer still screws with my TV's ability to correctly establish an eARC connection (which relies upon those ethernet pins).

[keith.f.kelly]

Any chance this fix might also apply to HDMI pins 14 and 19, which are the "ethernet over HDMI" pins responsible for eARC? Because even with the CEC pin (13) removed from the equation, my MiSTer still screws with my TV's ability to correctly establish an eARC connection (which relies upon those ethernet pins).

The DE-10 Nano schematics show that pin 19 is hard-wired to ground via a 10k resistor, and not connected to anything else. Pin 19 is also used as the "hot plug" pin, so it's possible it may play a role somehow in preventing my TV from properly detecting that an eARC receiver has been plugged into a different port.

The same schematics also indicate nothing about pin 14, suggesting it has just been left free-floating/non-connected. But that doesn't necessarily mean it was truly left non-connected in what was actually manufactured; it's possible it got terminated to ground or something due to it not being explicitly mentioned in the schematic at all. It'd be nice if someone with a bare DE-10 Nano lying around could check whether pin 14 really is non-connected.

[keith.f.kelly]

I taped over pins 14 and 19 on my CEC-less adapter, but it did not resolve the eARC problems, so it doesn't have anything to do with those pins. Must be one of the others.

[keith.f.kelly]

Pins 15 and 16 are the other two pins also "protected" by U34, so maybe it's one (or both) of them.

[keith.f.kelly]

Taping over pin 15 resolves my eARC issues.

I now have to wonder if U34 is somehow mis-wired or mis-used by the DE-10 Nano. Here's the datasheet for that component:

https://www.ti.com/product/TPD4E001

[keith.f.kelly]

The U34 pin connections in the DE-10 Nano schematic would match up with the "DBV or DCK" packages... but the "DRL" or "DCK2" packages apparently have identical sizes but with different pinouts. I wonder if someone chose the wrong package such that the pinout of U34 doesn't actually match what the Nano's schematic expects?

[keith.f.kelly]

Would there be any real danger to disconnecting HDMI pin 15 from U34 as well? Looks to me like it isn't hooked into any other chips/logic, but just ultimately runs to 5V+.

[hitm4n]

Ooooof. I've just had a nightmare with this issue. And its not quite over, please read if you are involved with this issue, i know i go on a bit but its all relevant. Especially the PS5 bragging.

Sony Bravia 65" TV, only 1 year old or so. Decent Philips soundbar with ARC. Recently bought MiSTer and hooked it up to tv. Also recently built an emulation PC, hooked that up too, needed a 1 in 5 out HDMI switcher, so that was also bought and installed. HDMI cable reach was an issue to some devices as well, so some new cables were bought and a little cable swapping done. Everything plumbed in, everything working (so it seemed).

OK, so far so good. I don't use my soundbar a lot, i certainly don't allow my TV to power it up by itself using that ARC and auto switch to it, but i do allow the audio to go to it when i manually turn it on. So Bravia sync is enabled, but the power on and off options are off. If i do power on the soundbar, the TV sees it and sends the audio (at least it used to).

Anyway, a while after installing all the above, we fancied watching a film with the soundbar on to give it some oompf so i turned it on. NO SOUND. TV didn't even acknowledge that sound had switched to the soundbar. However soundbar was on, flashing "HDMI ARC" on its display. If i manually changed the TV to "Audio System" from "TV Speakers" the sound just went dead on tv, still nothing from soundbar.

We watched what we needed to on the tv's speakers, then later last night i started to try to figure this out. TV got powered off, along with the soundbar, the HDMI switcher got unplugged, TV had an update so i did that (don't normally bother as i have no issues with TV thus far). I swapped HDMI cables around, i messed with the sync options, i tried things in isolation. The one thing i didn't try until just now as the MiSTer has been powered off this whole time, was unplug the HDMI cable from the MiSTer. Lo and behold, Bravia Sync now sees my soundbar and PS5 (don't be jealous guys), and sound outputs perfectly again.

FFFFFFFFFFUUUUUUUUUU!!!!!!!!!!

OK, so i bought an inline powerswitch so i don't have to keep plugging and unplugging the power cables, what the hell? Now i gotta unplug the HDMI cable too when not in use. Its not even powered up, how is it messing with or sending any signals ?

Whats the solution here. An older HDMI lead that doesn't comply with CEC standards maybe? I have read above about CECless cables, or adapaters with pins missing, but has anyone had a reliable result from purchasing these, and if so, please provide UK links so i can buy one. Someone else mentioned "push pin 13 out". In an HDMI lead?

Was CEC something introduced to HDMI cables at a particular revision (e.g. 2.0) and i could just source a 1.4 cable maybe?

And i do have an HDMI switcher and i do know that it does pass through CEC from my PS5 (are you turning green yet?), PS4 and PS3. I had to turn it off on all 3 consoles as with more than console on at once (one might be updating), the switcher and TV get in a right tizzle about which console is boss... (Its the PS5 of course - hehe).

I'll keep an eye out, anyone else who has had or seen these issues and found things out, please share the info. This must be an issue for other people hooking up MiSTer to a smart CEC/ARC enabled TV.

Ta.

[hitm4n]

OK, so i've tried a few things. Switched out cables, some of mine are old and it made no difference. Something weird happens even with the mister turned off. I just moved my BigBox PC from the HDMI switcher and plugged it direct to TV. Thats where its staying now. I don't really care about the orientation of everything as long as its all connected. The TV has 4 HDMI ports, one is ARC so obviously goes to the soundbar, leaving me just 3 inputs to play with. I have the mister, a pc, my ps3, ps4 and ps5. 5 into 3 just doesn't go so only option is a switcher. I got a nice 4k hdr2.2 bla bla compliant 1 in 5 out. Works lovely so long as all the CEC stuff on the consoles is disbaled so they don't fight.

So the mister, which was direct to TV, is now on the switcher. I figured introducing the switcher between the mister and the tv might just interrupt the dirty talk and slide past this issue. But no joy. Soon as i plugged the HDMI in to the switcher my audio dropped from the soundbar back to my TV, soo as i unplugged the mister from the switcher, audio came back on the soundbar.

I'm certain i need either a special cable, or like the post i see above, scrape the line away on the PCB. That seems a bit risky and i would need some recommendations on whether thats a good idea or not. No-one seemed to comment too much on pjtonge's fix but it looks and sounds very feasible to me and reasonably explains the nature of this issue.

What do you guys think is the best course of action?
At the moment, i am unplugging the HDMi cable from the switcher to isolate it, i'd rather break the HDMI port on that switcher than on the DE10, but i really would like to just leave everything set up. Sigh.

[mapf]

It might be worth to test a CEC blocker. Example: https://www.amazon.de/dp/B07X3MJCX5

[hitm4n]

I've PMd pjtonge for some further info on his solution, i'd really like to understand why this is an issue and if his fix was actually the same as using the adapter (which is the solution i think i will try first). Thanks for the reminder and link mapf.

I translated the german amazon title for that...
Sperre; Adapter für eine Unterbrechung des CEC-Signals; HDMI Steuerkanalsperre; Problemlösung bei HDMI-Verteilern und Multiroom-Systemen
gives me "lock; Adapter for an interruption of the CEC signal; HDMI control channel lock; Problem solving with HDMI distributors and multiroom systems"

I have to order from Amazon UK, so its a bit upsetting when this one https://www.amazon.de/dp/B01CWFRQNY/ is 4.10 euro

and this one on UK Amazon is https://www.amazon.com/dp/B00DL48KVI is twice the price at £9.38 + £1.99 delivery. £11.33. What a rip off.

Has anyone found a cheaper one for a uk buyer?

Thanks.

[hitm4n]

Yay. Not quite as neat as the Lindy adapter, but i found this. £4.99 with free delivery.

https://www.amazon.co.uk/gp/product/B01IKQO92K/

Ordered one and fingers crossed.

[mapf]

This looks like the same cheap adapter, but is currently unavailable on amazon.co.uk. https://www.amazon.co.uk/dp/B07X3MJCX5

[hitm4n]

Yay. Not quite as neat as the Lindy adapter, but i found this. £4.99 with free delivery.
https://www.amazon.co.uk/gp/product/B01IKQO92K/
Ordered one and fingers crossed.

Happy to confirm, this cable worked great. Nice and cheap, removes CEC. All connected up, MiSTer is turned off and soundbar on TV is working fine.

[pacoarcade]

So, if you're using HDMI at all, it's probably just a really good idea to get one of these little booster devices and install it, to electrically isolate things. And if you're putting MiSTer inside of a larger case of some kind, it's probably an even better idea to install one of these inside of the case, so that the HDMI port exposed on the outside of the case is already electrically isolated.

Thank you for the heads up. So the ideal solution would be to use the buffer and pin 13 (CEC) removal?

Is the HDMI buffer recommended if you use a HDMI to VGA converter? or this converter acts as a buffer so it's not needed?

[dakbluemonkey]

I've been having the CEC issue with my Sony Bravia TV after plugging in the DE10.

I got one of those Lindy CECless adaptors and it didn't fix the issue... I bought it from amazon in December... It turns out the CEC pin13 was still connected! Useless!

I cut the pin out by hand, and it solved the problem immediately... I documented the process on twitter...

[Zesty]

I've been having similar issues with my MiSTer and stumbled across this thread. Please tell me if this is a fair summary of what we know so far...

• Problem 1: As soon as you connect the DE10-Nano to your AV setup it can disrupt CEC-related features in every connected device, or lead to several other issues listed in the first post.
  
  
• Cause: The DE10-Nano's HDMI output is wired incorrectly. At the very least, pin 13 is completely wrong. This is not caused by (and cannot be fixed by) any current MiSTer project code or hardware.
  
  
• Solution: Place some sort of CEC-free HDMI passthrough device between the MiSTer and your other devices to prevent contact with the faulty pin. This can be done using an adapter like the Lindy, a modified cable, or any other HDMI pass-through device that has pin 13 disconnected. This will prevent the DE10 from disrupting the CEC functions of other devices, and possibly prevent most of the other issues as well. Since CEC is optional (and MiSTer doesn't use it anyway) it can be safely disconnected.

Unfortunately...

• Problem 2: Some MiSTer users may experience issues with HDMI ARC/eARC even after solving the pin 13 issue.
  
  
• Cause: Unknown. Possibly more hardware issues with the DE-10's HDMI output.
  
  
• Solution: Possibly solved by disconnecting pin 15 (serial clock for DDC) in the same manner as pin 13.

So, if I've got all that right, it seems like users who rely on HDMI ARC/eARC/CEC might benefit from a cable or passthrough device that disconnects several pins. The question is: which pins? Or would it be better to do some sort of internal mod that fixes or disconnects the faulty pins at the source?

Also, if we're disconnecting the DDC clock pin (15), should we also disconnect the DDC serial data pin (16) or is it fine to have one without the other? Does MiSTer use any DDC features like EDID?

[hitm4n]

To the best of my knowledge, having overcome this issue myself with an ARC soundbar (uses CEC)...

Problem 1: As soon as you connect the DE10-Nano to your AV setup it can disrupt CEC-related features in every connected device, or lead to several other issues listed in the first post.

Doesn't affect all users with AV equipment and soundbars. Seems common on Sony TVs, Sony Bravias (which i have) seem to not want to see a soundbar IF the MiSTer is connected. Even if its turned off (read back and see posts about pin 13 dropping voltage to zero when TV expects 5v or something like that).

The DE10-Nano's HDMI output is wired incorrectly. At the very least, pin 13 is completely wrong. This is not caused by (and cannot be fixed by) any current MiSTer project code or hardware.

Its not wired incorrectly, its just not wired to absolute standards. And indeed, someone pointed out that this pin shouldn't even be wired at all. The schematics have shown "DNC" (Do Not Connect) on the PCB.

Solution: Place some sort of CEC-free HDMI passthrough device between the MiSTer and your other devices to prevent contact with the faulty pin. This can be done using an adapter like the Lindy, a modified cable, or any other HDMI pass-through device that has pin 13 disconnected. This will prevent the DE10 from disrupting the CEC functions of other devices, and possibly prevent most of the other issues as well. Since CEC is optional (and MiSTer doesn't use it anyway) it can be safely disconnected.

Safe to disable pin13. The cable i bought (look at my post a few up), worked beautifully. Soundbar works a treat now, zero issues and not a single issue with the MiSTer output using it.

Unfortunately...
Problem 2: Some MiSTer users may experience issues with HDMI ARC/eARC even after solving the pin 13 issue.

I'm not sure this is true. Everyone i've seen post who has had this issue has resolved it with the pin13 fix. The only ones that didn't bought a Lindy adapter that still had pin13 connected. These were faulty stock from Amazon i believe. My cable is brilliant. Works and was cheaper.

Cause: Unknown. Possibly more hardware issues with the DE-10's HDMI output.

Again, not sure this is true. I haven't read about other HDMI issues related to pin13 and i read a lot of forums and posts (not just here) when trying to figure this out for myself. Even Sony forums and AV forums as i couldn't believe it was coming from the MiSTer. My problem was when i set up my MiSTer i did a big rewire of all things HDMI and introduced a new PC into the mix as well. So it was hard to pinpoint why the damn soundbar suddenly stopped working. At one point i thought with all the moving around i'd actually broken my soundbar.

Solution: Possibly solved by disconnecting pin 15 (serial clock for DDC) in the same manner as pin 13.

This might be something you need to do, but i certainly didn't and i would try the cable i bought first as its your most likely fix. Pin15 fixes may be for very old HDMI cables, or maybe even very very new ones? I don't know enough about pin15 as pin13 was the route i went with and which worked for me.

So, if I've got all that right, it seems like users who rely on HDMI ARC/eARC/CEC might benefit from a cable or passthrough device that disconnects several pins. The question is: which pins? Or would it be better to do some sort of internal mod that fixes or disconnects the faulty pins at the source?

Someone did scrape the line away on their MiSTer PCB. That will work too, but its a pretty scary and untidy solution.

Also, if we're disconnecting the DDC clock pin (15), should we also disconnect the DDC serial data pin (16) or is it fine to have one without the other? Does MiSTer use any DDC features like EDID?

Now this i don't know. Totally beyond me, but i hope this info helps.

[Zesty]

I appreciate the info. I'm also using a soundbar and a Bravia TV, so I'll definitely pick up one of the adapters.

For the pin 15 stuff, I was talking about the posts on page 2 where OP found additional HDMI issues that were solved by taping over pin 15. They start here:

NEW INFO: There is STILL something electrically weird going on with MiSTer's HDMI port. Even using the CEC-less cable and the CableMatters booster, if the MiSTer is plugged into my new 4K Samsung Q90T television, then the TV is unable to correctly detect that it is connected to an eARC AV receiver on a different input. Something about the MiSTer electrically messes with the eARC communication mechanism; possible some other pin that is only used for eARC?

Hopefully someone who knows more about the DDC stuff is able to weigh in so we can figure that part out. It's good that the existing CEC adapters seem to solve 99% of the problems people have observed, but it also wouldn't be too hard to make a custom HDMI coupler or cable if we need to.

[Chancer]

Just thought I'd add my experience with this issue in case it helps anyone.

I recently moved house and after setting up my consoles and TV / AV receiver I was having all sorts of ARC problems, no sound being passed back to the receiver etc. After much testing, fumbling with TV and device settings I realised it was the MiSTer causing issues whenever it was connected to the receiver.

I couldn't figure out why this was suddenly an issue when it's used to work perfectly at my old house? Anyway, I eventually found my way to this thread and reading through the posts I realised something that had changed from my last setup. I was now running my MiSTer HDMI directly into the AV receiver, whereas previously out was going through an HDMI switcher first.

I just added the HDMI switcher back into the setup, and just like that the whole thing works great as before. No more ARC issues. Based on this thread, I'm guessing the switcher strips out CEC from the cable.

This is the switcher I'm using in case this is helpful for anyone:

https://smile.amazon.co.uk/dp/B075R2DFJ1/

[keith.f.kelly]

Just circling back on this, since folks seem to have gotten lost in the details I posted months ago:

You have to disconnect BOTH pins 13 (via the CEC-less cable I recommended earlier) AND pin 15 (via a microscopic piece of masking tape applied to the cable end) to resolve all known issues. Lifting pin 13 alone is not sufficient.

I've thoroughly searched the interwebz, but nobody seems to make an HDMI adapter or cable that lifts BOTH pins. If someone out there can do that, or come up with a provably safe and easy mod to the DE-10 Nano itself to disconnect both pins, you'll be my hero, because that tiny piece of masking tape over pin 15 is a pretty ghetto solution.