RGB to HDMI using a Pi Zero and a small CPLD

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gbrigden
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by gbrigden » Tue Jan 28, 2020 1:52 pm

I have been attempting to use a RGB --> Scart Lead --> HDMI Upscaler box without any success.
I am struggling to even get the RGB --> Scart working.
One of these adapters for my dusted down BBC Micro B sounds to be the perfect answer. I take it that assembling the board isnt really for the casual DIY'er or would it possible with a limited soldering skill ability be able to assemble these boards?

Thanks

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IanB
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by IanB » Wed Jan 29, 2020 4:01 am

hoglet wrote:
Tue Jan 28, 2020 11:28 am
Even the Spectrum has proved somewhat of a struggle, and it's not current possible to differentiate all the bright/normal colours.
Just to add that it's only the 48K Spectrum with YUV output on the edge connector that has this limitation. All the other later Spectrums with digital or analog RGB outputs can display all bright/normal colours correctly.

I have a number of bare 6 bit boards available if anyone needs one and I'm also looking at getting a batch built up in China as I need about a dozen of them just for myself. If anyone is interested in a built up one (or more than one) then please post so I can get an idea of the quantity I should order.
Last edited by IanB on Thu Feb 06, 2020 1:25 am, edited 1 time in total.

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hoglet
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by hoglet » Wed Jan 29, 2020 7:51 am

IanB wrote:
Wed Jan 29, 2020 4:01 am
I have a number of bare 6 bit boards available if anyone needs one and I'm also looking at getting a batch built up in China as I need about a dozen of them just for myself. If anyone is interested in a built up one (or more than one) then please post so I can get an idea of the quantity I should order.
Ian, I would suggest starting a new thread to coordinate this build. This is now a huge thread, and posts are easily missed.

Dave

aotta
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by aotta » Wed Jan 29, 2020 1:17 pm

i agree with Dave's idea of a new thread for 6bit version, and asking if possible some more support for this branch in the wiki… i know it's still a "Dev" project, but i'm reading GitHub's pages since a week, and haven't understood yet how to get the correct PI firmware and updating the CPLD.. i'd like an "idiot proof" guide as for the Classic RGBtoHDMI version :D

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marcusjambler
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by marcusjambler » Wed Jan 29, 2020 1:23 pm

If anyone is interested in a built up one
Putting hand up for a built unit.

Marcus

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BigEd
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by BigEd » Wed Jan 29, 2020 1:45 pm

It's notable that Judgebeeb tried and failed to give away interface boards. I wonder if he'd've shifted more if he'd charged £20. Certainly it's a great product!

I think I'd suggest that we distinguish a project thread - like this - from a product thread, like Ian might launch. I'd suggest a catchy name too. "8bit HDMI Dongle" is more or less how I think of the thing - it's a brilliant use of a Pi and a small CPLD, but that's not uppermost in the mind of the user.

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by th3bar0n » Wed Jan 29, 2020 2:16 pm

I'd definitely be interested in an "8bit hdmi dongle"!

Looking forward to the new thread.

gbrigden
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by gbrigden » Wed Jan 29, 2020 3:36 pm

At £20 for the dongle, i'd be happy to pay. Afterall with the different cables and upscalers i have bought and failed, i think it is a small price to pay

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hoglet
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by hoglet » Wed Jan 29, 2020 3:52 pm

gbrigden wrote:
Wed Jan 29, 2020 3:36 pm
At £20 for the dongle, i'd be happy to pay. Afterall with the different cables and upscalers i have bought and failed, i think it is a small price to pay
To be fair, I would expect it to me more expensive than £20.

Remklep
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by Remklep » Wed Jan 29, 2020 4:05 pm

Just to be sure, before I can say how many I need, what can I use it for.
I have a Model B+128k and a Master 128.
I also have one VideoNuLa to be put in either of the machines.

Would I benefit from an 8-bit hdmi dongle on both machines?
BBC Model B+ 64K, 128K Memory Mod, RetroClinic External PiDirect with Raspberry Pi 3B.
BBC Master 128, RetroClinic Internal PiDirect with Raspberry Zero, TurboSPI MMC, RobC's VideoNuLa, Gotek Floppy Emulator.

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by aotta » Wed Jan 29, 2020 4:12 pm

8 bit dongle? I think noone is working at this project, but using a pi3 (or the last pi4) instead of pi zero, could open new scenarios..

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IanB
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by IanB » Sat Feb 01, 2020 3:04 pm

hoglet wrote:
Wed Jan 29, 2020 7:51 am
Ian, I would suggest starting a new thread to coordinate this build. This is now a huge thread, and posts are easily missed.
OK I'll start a new thread once I've had a chance to get some quotes. The main issue seems to be the CPLD as JLC don't have that in their list of stocked parts so I'll have to look at other PCB manufacturers.

The other thing to consider is whether to redesign the PCB with more surface mount parts. At the moment I minimised the surface mount parts to make it easier to hand assemble but for a manufacturing run it would make more sense to change the terminating resistors, the switches and even the LEDs to surface mount.

sixedup
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by sixedup » Thu Feb 20, 2020 1:55 am

IanB wrote:
Wed Jan 29, 2020 4:01 am
If anyone is interested in a built up one (or more than one) then please post so I can get an idea of the quantity I should order.
I'm interested in one too.
Richard

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TheArduinoGuy
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by TheArduinoGuy » Thu Feb 20, 2020 5:34 am

My PCBs have arrived.

Image

Just need to source the parts now.

Mike

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hoglet
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by hoglet » Thu Feb 20, 2020 7:38 am

TheArduinoGuy wrote:
Thu Feb 20, 2020 5:34 am
Just need to source the parts now.
There is a Bill of Materials on the Wiki:
https://github.com/hoglet67/RGBtoHDMI/w ... t-Board%29

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by Remklep » Thu Feb 20, 2020 8:10 am

I would like a pcb, if you have any left.

Thanks,
Danny
BBC Model B+ 64K, 128K Memory Mod, RetroClinic External PiDirect with Raspberry Pi 3B.
BBC Master 128, RetroClinic Internal PiDirect with Raspberry Zero, TurboSPI MMC, RobC's VideoNuLa, Gotek Floppy Emulator.

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LordVaderUK
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by LordVaderUK » Wed Feb 26, 2020 1:34 pm

IanB wrote:
Wed Jan 29, 2020 4:01 am
If anyone is interested in a built up one (or more than one) then please post so I can get an idea of the quantity I should order.
Yes please @ianb :)
Loving my BBC Master 128

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TheArduinoGuy
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by TheArduinoGuy » Wed Feb 26, 2020 2:19 pm

Remklep wrote:
Thu Feb 20, 2020 8:10 am
I would like a pcb, if you have any left.

Thanks,
Danny
Sure, if anyone wants just the bare PCB then PM me.

Remklep
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by Remklep » Wed Feb 26, 2020 3:50 pm

TheArduinoGuy wrote:
Wed Feb 26, 2020 2:19 pm
Remklep wrote:
Thu Feb 20, 2020 8:10 am
I would like a pcb, if you have any left.

Thanks,
Danny
Sure, if anyone wants just the bare PCB then PM me.
Would an all-inclusive kit be possible?
I can solder myself.

Danny
BBC Model B+ 64K, 128K Memory Mod, RetroClinic External PiDirect with Raspberry Pi 3B.
BBC Master 128, RetroClinic Internal PiDirect with Raspberry Zero, TurboSPI MMC, RobC's VideoNuLa, Gotek Floppy Emulator.

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by aotta » Sat Mar 07, 2020 6:04 pm

i made a couple of RGBtoHDMI boards, and now i'm soldering the last 6bit version by IanB, but i'm a bit confused...
i read the cpld is "self programming", but i didn't understand how it works: i can use the releas version of the sdcard's files on github (RC5 dated 17/2 is the last i found) and simply power on the board?

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hoglet
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by hoglet » Sat Mar 07, 2020 6:12 pm

aotta wrote:
Sat Mar 07, 2020 6:04 pm
i made a couple of RGBtoHDMI boards, and now i'm soldering the last 6bit version by IanB, but i'm a bit confused...
i read the cpld is "self programming", but i didn't understand how it works: i can use the releas version of the sdcard's files on github (RC5 dated 17/2 is the last i found) and simply power on the board?
Yes, it should detect the CPLD as unprogrammed, and immediately bring up the CPLD Recovery Menu. Use the up/down buttons to select 6BIT_RGB_v73 and then press OK. Programming takes about 30 seconds, and the system will then reboot.

Dave

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by aotta » Sat Mar 07, 2020 6:19 pm

hoglet wrote:
Sat Mar 07, 2020 6:12 pm
aotta wrote:
Sat Mar 07, 2020 6:04 pm
i made a couple of RGBtoHDMI boards, and now i'm soldering the last 6bit version by IanB, but i'm a bit confused...
i read the cpld is "self programming", but i didn't understand how it works: i can use the releas version of the sdcard's files on github (RC5 dated 17/2 is the last i found) and simply power on the board?
Yes, it should detect the CPLD as unprogrammed, and immediately bring up the CPLD Recovery Menu. Use the up/down buttons to select 6BIT_RGB_v73 and then press OK. Programming takes about 30 seconds, and the system will then reboot.

Dave
Thank you Dave, really more easy in this way, i can't wait to try it!

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IanB
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by IanB » Sat Mar 07, 2020 6:59 pm

aotta wrote:
Sat Mar 07, 2020 6:04 pm
i made a couple of RGBtoHDMI boards, and now i'm soldering the last 6bit version by IanB, but i'm a bit confused...
i read the cpld is "self programming", but i didn't understand how it works: i can use the releas version of the sdcard's files on github (RC5 dated 17/2 is the last i found) and simply power on the board?
There is a slightly more recent RC6 available now.

We've substantially updated the wiki over the past couple of months and it now covers most things:
https://github.com/hoglet67/RGBtoHDMI/wiki
Although not 100% finished, it now covers CPLD programming, a quick start guide, a reference guide and how to setup a new profile.
There's even a gallery of screencaps of most of the supported machines.

CPLD programming is linked from the sidebar but here is the direct link:
https://github.com/hoglet67/RGBtoHDMI/w ... rogramming

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by aotta » Sun Mar 08, 2020 8:50 pm

Very helpful, thank you for the update! i made (after burning a lot of xilinx IC... ) two hat, and waiting for some components to test the analog board, but the BOM in the wiki doesn't match to the V2 board i've, so i'd to use the schematics.

But I have an issue with one of the 2 hat i made: the colour seems not mixed fine in one of them, and with some blank dots in column into the characters:
capture9.png
The one working fine, and
capture8.png
the strange one!

May be a bad soldering of CPLD?

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hoglet
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by hoglet » Sun Mar 08, 2020 8:53 pm

Have you run the auto-calibration?

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by aotta » Sun Mar 08, 2020 9:03 pm

hoglet wrote:
Sun Mar 08, 2020 8:53 pm
Have you run the auto-calibration?
Yes, but with no change. I got "genlock failed" while auto calibrating, but it's the same with the other that's shows rights pixel

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hoglet
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by hoglet » Sun Mar 08, 2020 9:08 pm

aotta wrote:
Sun Mar 08, 2020 9:03 pm
Yes, but with no change. I got "genlock failed" while auto calibrating, but it's the same with the other that's shows rights pixel
To be honest, both images look poor, so something is not right...

Genlock failed usually means that you have not set the Resolution setting to a 50Hz mode.

Did you work through the Quick Start Guide?
https://github.com/hoglet67/RGBtoHDMI/w ... tart-Guide

Also, I noticed that the machine has a VideoNuLA ROM installed.

Is there a VideoNuLA fitted to this machine?

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by aotta » Sun Mar 08, 2020 9:21 pm

hoglet wrote:
Sun Mar 08, 2020 9:08 pm
aotta wrote:
Sun Mar 08, 2020 9:03 pm
Yes, but with no change. I got "genlock failed" while auto calibrating, but it's the same with the other that's shows rights pixel
To be honest, both images look poor, so something is not right...

Genlock failed usually means that you have not set the Resolution setting to a 50Hz mode.

Did you work through the Quick Start Guide?
https://github.com/hoglet67/RGBtoHDMI/w ... tart-Guide

Also, I noticed that the machine has a VideoNuLA ROM installed.

Is there a VideoNuLA fitted to this machine?
i tested some different resolution, at 50Hz too, and no difference.
Yes, it's fitted a videonula on the Micro i'm using for test, but with other 6bit hat (and with the other two "original" RGBtoHDMI i usually use) i've not issue with videonula.

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by hoglet » Sun Mar 08, 2020 9:43 pm

What happens if you put up a completely white screen on the Beeb?

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by aotta » Sun Mar 08, 2020 10:02 pm

Dave, now i've no more output from Micro on the screen, so i'm afraid the CPLD is gone (i've desoldered once with hot gun, and probably i damaged it)
Thank you for support, but tomorrow i'll try to make a new one (i've 5 xilinx left... i hope they'll be enough for my bad soldering!)

as not said, my mystake! while testing i get a not supported resolution... :oops:
that's the white on white output, if it's of some help in finding the trouble:
capture2.png

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