Human Interface Board -TV out issue?

tdg8934

Has anyone been able to get the special audio/video connection on the Human Interface Board to work for TV and audio. I bought a couple of cables from Radio Shack and none of them work 100% on 2 different TVs.

The Human Interface Board manual refers in section 10 as TRRS and TRS cables.

(10) Audio and Composite Video Output The A/V connector works with both 1/8” audio devices, such as headphones and speakers, and with baseband video devices, such as TVs. The left channel draws its signal from Propeller I/O pin P11, the right channel from P10, and the video from P12 through P15, with P12 as the most significant bit, P14 as the least significant bit, and P15 as the aural subcarrier. The TRRS connector is compatible with TRS cables, with the tip carrying left-channel audio, the ring carrying right-channel audio, and the sleeve acting as the return path. When used with a TRRS cable, the tip carries left-channel audio, the outer ring carries right-channel audio, the inner ring carries video, and the sleeve acts as the return path. The signals are all line level signals with a 75 ohm impedance. The amplifier includes a 6th order low-pass filter with an 8 MHz cutoff to significantly reduce the switching noise from the Propeller's duty mode outputs.

In the last picture you will see the TRS cable slightly pulled out and it works but could never get audio, unless I used a set of headphones. So Video is not being accessible.

Ideas?

Tim

tdg8934

I did some more troubleshooting with a meter (ohm and continuity) and found that the manual is correct but it doesn't match to a standard 1/8" jack to RCA video/audio cable readily available at Radio Shack and other electronic stores. TRRS connectors seem to be "evenly" spaced on the 1/8" jack "rings" end. See the first picture. The ones at Radio Shack (Standard 1/8" jack to A/V cables) have "longer" bottom ring spacing AND NOT CONFIGURED THE SAME. As you can see by my other attached pictures. The Radio Shack "longer bottom ring spacing" cable has to be pulled back to get the "even" spacing like the TRRS cables are. But more importantly the audio and video RCA connectors on 1/8" jack to A/V connectors from Radio Shack and other stores (long ring spacing) - are not the same as TRRS. From the picture, you can see that I am plugging in the "White" RCA connector (normally used for audio) into where the yellow video in jack should go into the TV.

Lesson learned - when shopping for TRRS a/v cable, look for the "evenly" spaced rings and preferably if it states "TRRS". However, I don't know where these can be purchased locally. Parallax needs to stock these TRRS cables.

Tim

skylight

I managed to get hold of a TRRS to Rca cable (took some searching for) it looks like it has evenly spaced rings and pin (4 connections) the video is trying to work, It's not a connection problem I think I have but a Wrong signal problem as I can see some text appearing but it is diagonally chopped and scrolling with a white noisy band to the right of screen NSTC instead of PAL?

skylight

Just tried Real Number.spin which uses TV terminal and TV spin files and same scrolling until I tried your trick with pulling the TRRS plug out one segment and Voila it works!!
Too late to try tonight but perhaps The RCA' plugs are plugged into the tv wrong? connected as per colours red to red yellow to yellow etc perhaps the TRRS socket is wired differently to the standard colour setup? will try different combinations of plugging tomorrow to find the correct video connection on my cable and post the result.

tdg8934

That's the issue. I had not heard of TRRS cables before as they come in many configurations, some with audio and microphone connections and some with audio and video connections. To make it worse, someone who doesn't know this will simply go to their local Radio Shack or buy online a 1/8" jack to A/V cable as many consumers are aware of - and purchase those as they look identical except they are not evenly spaced. However from your description it looks like your evenly spaced TRRS cable is wired up like a standard 1/8" jack to A/V cable.

So the question is how does the user know if they have the right TRRS cable with Video on the 3rd spaced ring and video is not on the tip (as in a 1/8" jack to A/V cable)?

Parallax or someone should stock the correct recommended TRRS cable sold with the Human Interface Board,

Tim

skylight

I'm hoping that swapping the coloured RCA's around will find the correct colour for video Yellow is normally the standard, at the moment I have yellow plugged to yellow at the TV end but with the TRRS plug one segment out of the TRRS socket on the HIB I'm hoping a simple swop of colours at the TV will solve the problem.

One question is the standard different in the US and yellow is not video?

tdg8934

Take a look at my last pictures sent. The "white" audio RCA connector worked for Video into the TV on the incorrect slightly backed out 1/8" jack to A/V cable not TRRS. "Yellow" is the standard color for video on these RCA connectors.

Tim

skylight

tdg8934 wrote: »

The "white" audio RCA connector worked for Video into the TV on the incorrect slightly backed out 1/8" jack to A/V cable not TRRS. "Yellow" is the standard color for video on these RCA connectors.

Tim

Thats strange because I have done exactly the same yet the standard yellow plug is connected as video not white. Seems like we have different permutations
The cable I have is packaged as 3.5mm(1/8") 4 pin to three RCA's and was sold as TRRS 3.5mm to 3RCA

tdg8934

Ok. It sounds like you have a TRRS cable which is different than a 1/8" jack with A/V RCA connectors. So, in your case the yellow is what should be working on this TRRS cable for video. I dont know if there is any differences for American vs UK video. I would suspect there is not (only NTSC and PAL which is broadcasting not really baseband video I think).

Tim

tdg8934

OldbitCollector (Jeff) at Propellerpowered.us has the correct (as best as can be - working TRRS cables) for the Human Interface Board.

http://propellerpowered.us/index.php?route=product/product&product_id=200

Tim