The F18a DIY alternative with HDMI :)

[Duewester]

Taking apart one of 6flat cables doesn't look like a good idea. Once crimped, taking it apart will impact the integrity of the connection.

I partially installed the Ti RF shield (the flat cable prevents proper installation) and tried both versions. No joy and no improvement.

[retrocanada76]

12 hours ago, Hans23 said:

I'm looking at the datasheet and it seems that the minimum Vdd/Vref voltage is 2.7V.  Does that not mean that I can't really turn the reference voltage down to my output level of 1.7V?

i don't know if we need a transistor or something. it's strange because on msx is working from the composite rca output shouldn't be different

[retrocanada76]

So what am i missing here? First shot, v2 board, v2 core getting audio from pin 3 (connector)

[retrocanada76]

@Duewester are you using the 9958 v2 by any chance ? The V2 9918 worked first shot for me.

 

try downloading again the core i re-compiled and re-pushed. who knows ?

 

https://github.com/lfantoniosi/tn_vdp/blob/main/fpga/tn_vdp_v2_v9918/impl/pnr/tn_vdp.fs

[Duewester]

@retrocanada76, Oh, I get that far all the time. About 3 out of 10 tries. I even get to the FinalGromm99 cartridge sometimes. Occasionally I can select a game and get to the opening screen.

I tried the 9958 code early on and it wouldn't even boot the Ti. Just some strange wide green bars and loud screeching.

I'll try the recompiled code and get back to you.

Edited July 4, 2023 by Duewester

[Duewester]

If a picture is worth a thousand words, I hope this video will be worth a few more.

 @retrocanada76 This is your latest V2 software. I've tried it on two V2 boards and the original FAT board. I tried it with and without sound connected to pin 3 of 9901. The sound you hear in this video is from a speaker connected to the Audio/Video out connection of the Ti, not the HDMI.

 

 

 

[retrocanada76]

Can you try a different monitor?

 

this version v2 uses a different hdmi output (because of audio)

[retrocanada76]

Also suggest everybody using this 

 

https://www.amazon.ca/axGear-Repeater-Booster-Extender-Amplifier/dp/B07DFWW8NC

 

it reencodes the video and prevents the tv from turning on the tang.

 

also @Duewester try turning on the ti then you connect the hdmi for a test

[Duewester]

11 hours ago, retrocanada76 said:

Can you try a different monitor?

 

this version v2 uses a different hdmi output (because of audio)

I tried a different and newer TV and cable after my last post and never could get a clean boot. Always had same split screen.

 

So, a different HDMI, that's the difference. I wondered what was different (other than connection method).

Edited July 4, 2023 by Duewester

[retrocanada76]

And the stand alone splash screeb disconnected from the board?

[retrocanada76]

if the screen posiition is always the same you can try modifying this line in the code, line 262 of top.v file:

 

            .START_Y(0) )

 

since it looks exactly in the middle try:

 

            .START_Y(262) )

 

this value can be any from 0 to 524 or try this one attached i built for you at 262. If 262 is not good you can try other values.

 

maybe some tangs are different from others ? I cannot explain this.

 

tn_vdp.zip

[Duewester]

Todays' adventure in Ti-Tangland.

 

Made new short flat 20 pin IDC cables - things got a little better.

Got another new HMDI cable - No change.

Flat cables for interior HDMI from Fat board do not work on V2 boards (?)

Connecting Audio Pin on adapter board to Ti Shield stops static on hdmi but does not provide sound. Connecting Audio to TI Audio out (Pin 3 on plug) lots of static but boots.

Removing the amp chip doesn't improve performance or eliminate static.

[wierd_w]

Perhaps try a bit of oldschool 80 wire ata133 cable, and just let it hang off the side of the idc header?

 

Cutting one between the primary and secondary IDE connectors (and thus very short) might be what you need. Extra noise suppression with interspersed grounds

[Duewester]

6 minutes ago, wierd_w said:

Perhaps try a bit of oldschool 80 wire ata133 cable, and just let it hang off the side of the idc header?

 

Cutting one between the primary and secondary IDE connectors (and thus very short) might be what you need. Extra noise suppression with interspersed grounds

@wierd_w I too had that thought but, that's a lot of bulky, stiff stuff to try to get into place in the case.

@retrocanada76 said earlier that he used a different HDMI out to get the Sound so I'm wondering if maybe the diode is now in the wrong place. Anyway that's where I'm looking now.

[retrocanada76]

@Duewester did youi try the fgpa code I attached here ?

 

[Duewester]

On 7/6/2023 at 12:28 AM, retrocanada76 said:

@Duewester did youi try the fgpa code I attached here ?

 

Hey @retrocanada76, sorry haven't been here on this project lately.

I broke out a Ti-99/4a with a F18a in it and swapped out the F18a with the Tang. I repeated all my Version 1 and version 2 softwares on the Ti-Tang and the Original Ti-Fat board. The Fat board works and the version 2 boards and V2 softwares don't. Sames as the original Ti-99/4a. New Tang board with V1 software works but no sound.

 

Yes I did try the new file. It off sets the screen half way 100% of the times I booted. So, not the answer.

 

The 9918 V2 is not stable on 3 Tangs and 2 Ti-Tang hardware setups. Software version 1 on new Tang board works quite well if the Audio pin is connected to ground. Software version 2 on T-Tang with Audio connected to Pin 3 of the connector does produce sound - with so much static my old ears didn't realize it was working. I had been disconnecting the audio as result of the noise. Now I see that Audio connected to Pin 3 does produce a stable output but a noisy one.

 

Another thing, only one 20 PIN idc configuration seems to work. I would have expected that as long as pin 1 on the board and cable was the same I could use any of the 4 possible configurations. Not so. So, there may be some issue with the wiring between either the 9918 interface board or the Tang board.

 

I'm on my last Tang 9k. I get the same results on all Tangs and board configurations so I'm confident in the board/Tang construction.

 

Todays conclusions/assumptions/observations

1. Version 2 software implements the audio amplifier and is more prone to board noise.
   1. Grounding the Audio connection will reduce noise. But, you get no sound.
2. Not every 20 pin cable configuration regardless of cable length is compatible with any output. Longer cables do get noisier.
3. I have tried so many HDMI flat cable and connectors on the new setup I can't count them. Most either don't work at all or produce so much noise it's unbelievable.
   1. One of these configs IS working just fine on my Frankennine with the Fat board in it.
4. Two different Ti-99/4a computers behave the same so not, the motherboard, power supply or number of socketed in chips.
5. Now that I have figured out the sound issue, time to move to the noise issue.
   1. Adding ground to HDMI shell doesn't work.
   2. Going from Amplifier pin 2 to connector pin 3 is even noisier.
   3. I need a shielded wire for next test - after dinner.

[retrocanada76]

hmm weird. Check the socket board if the pins are connected from both headers: pin 1 to pin 1 , 2 to 2 and so on. Maybe there is a factory defect ? I can get a signal from both inputs.

 on the tang mainboard I only tried the side with jumpers. I never populated to other one.

 

I'll take a look on the code, try to change few things to get a more stable signal. but for me it looks pretty stable already.

 

try removing the ADC chip and test without it. You are using the MCP3202 right ?

 

If you disconnect the VGA breaker from the FAT board V1 you can test the V2 code. This would help diagnosing if there is indeed a problem with the board.

 

 

[retrocanada76]

@Duewester hold your horses. I gave a try on my CX5M with the v2 board v2 9918 and I am getting the same video corruption. As I cannot explain now I can fix it.

 

[retrocanada76]

there seems to be some electrical shit happening here. maybe the flat cable wasn't a good idea at all.

 

strange that with Tang 20K it seems to work flawless.

 

I have a SD cartridge on my MSX when I put it I get these issues. Not happening with regular cartrigdes or no cartridge. Could it be that noise is doing it ?

[retrocanada76]

it seems to be the flat cable. I'll keep investigating

 

[Duewester]

@retrocanada76I am actually relieved that you see the problem as well.

I started looking for external noise sources by turning off my PC and my work Light (CFL). No difference in noise.

I then made a somewhat long flat cable and separated the wires into pairs. Boot issues and noise. on V2 software but works on V1 software with no sound though.

22 hours ago, retrocanada76 said:

hmm weird. Check the socket board if the pins are connected from both headers: pin 1 to pin 1 , 2 to 2 and so on. Maybe there is a factory defect ? I can get a signal from both inputs.

I wrung out the connections. Really had to look hard for trace that connects pin 1 to pin 2. Thought it might be bridge but I broke out an unused adapter plate and found it.

 

22 hours ago, retrocanada76 said:

try removing the ADC chip and test without it. You are using the MCP3202 right ?

 

If you disconnect the VGA breaker from the FAT board V1 you can test the V2 code. This would help diagnosing if there is indeed a problem with the board.

 

Pulled the ADC - Regular cycle of noise.

I breadboarded up a ADC to a FAT board and ran V1 and V2 software. No sound. Might be my breadboard. V2 software on FAT will eventually start making lots of noise with increasing volume. Although there is no sound - V1 on FAT board never makes noise or becomes unstable.

 

OBTW - I ran a shielded wire (piece of antenna coax) for the Audio and that didn't make any difference in the noise.

Edited July 10, 2023 by Duewester

[retrocanada76]

@Duewester sync the repo and try the new v2 9918

 

The hdmi was getting out of the sync with the vdp, now I force a reset everytime this happens (video mode changes, blank screens etc)

 

 

 

Now, if you disconnect audio you should get no audio. You can just pull the chip. The audio is very experimental, and as I said I am not an engineer. It may get noise in some systems.

Edited July 11, 2023 by retrocanada76

[retrocanada76]

v2 9958 is fixed too.

 

[retrocanada76]

so my electrical issues stemmed from a frayed cable and it should be very very short. I am talking about 3 inches tops

[craftsman1234]

1 hour ago, retrocanada76 said:

v2 9958 is fixed too.

 

Quick question could the sync issue also be in Version 1.  Asking due to the crashes in the ColecoVision.