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Forum Index : Microcontroller and PC projects : Waveshare 7 & 10" DVI displays
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| IanT Regular Member  Joined: 29/11/2016 Location: United KingdomPosts: 99 |
I've been thinking about how best to produce two simple Boot-to-Basic PicoMite systems as gifts for my two eldest grandchildren. A usable screen, with combined CPU unit, with full-sized external USB keyboard would seem to be a good solution, given their likely use. They don't need to be "portable" as such, just reasonably self-contained. I've noticed these 7"/10" DVI displays on the Waveshare site that provide a Pico socket on the back. They seem reasonably priced (£25'ish) and would save me a lot of work hacking a custom system. I can produce simple cases for them, together with plug-in mains power. https://www.waveshare.com/pico-dvi.htm?sku=25510 However, these displays use a pin-out that is different to the standard Picomite HDMI set-up. So my (quite probably dumb) question is - Is it possible to re-define the pins used for the HDMI signals? If so, will that then work with this "DVI" screen? Regards, IanT |
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| matherp Guru  Joined: 11/12/2012 Location: United KingdomPosts: 10007 |
No: the HSTX pins are hard wired in the RP2350 and can't be changed. |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7471 |
In theory one could make a hardware adapter to accept a Pico 2 and with a 40-pin plug on it to plug into the Waveshare socket. That would be an interesting exercise. A bit pointless as you can't have 1024x600 resolution though. . Edited 2025-05-01 22:05 by Mixtel90 Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| mozzie Regular Member Joined: 15/06/2020 Location: AustraliaPosts: 94 |
G'day IanT With a simple breadboard adapter these DVI screens work very well, the native 1024 x 600 resolution is a pain but they scale to whatever you drive them with. Can confirm 640x480,800x600,1024x768 and 1280x720 all work fine, haven't tried the others yet.     Photos don't do the real thing justice, this is the 7" version. Regards, Lyle. |
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| lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 3299 |
Very nice. I assume a JLCPCB board could do the configuring. Do you have a schematic? PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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| IanT Regular Member Joined: 29/11/2016 Location: United KingdomPosts: 99 |
Thank you for the replies everyone. Your solution looks like a really good fit for my need Mozzie. I can manage a bit of veroboard bodgery if necessary but will admit a JLCPCB board would be a much neater way to do it! For the small difference in price, I think I'll use the 10" display. Regards, IanT |
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| mozzie Regular Member Joined: 15/06/2020 Location: AustraliaPosts: 94 |
G'day, See below for... well... ummm... a diagram...  You loose GP8,9,10,11 on the PICO side and GP16,17,18,19 on the DVI side using veroboard. These could be connected with jumpers of course with a bit of juggling. Use option HDMI PINS 1,3,6,4 if you do it this way. Also tested 720x400 and 848x480 resolution and can confirm they work as widescreen modes.  Regards, Lyle. |
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| IanT Regular Member Joined: 29/11/2016 Location: United KingdomPosts: 99 |
Thank you for that Lyle. It took me a few seconds to understand what I was looking at but I get the general idea. I have a 'Babysit' day today but I will print this out and look at it in more detail this evening. That's assuming I have any life/energy left in me by then. This child is nearly 3yrs old (and not quite yet up to learning Basic) but he can still run us ragged :-) Looking at the debate about a 'PicoCalc' alternative on another thread, I can see the attraction of a Psion (remember them?) type hand held computer/organiser. However, I think a standalone MMB unit, with usable keyboard and larger screen would be preferable for many people... ..and of course I also have an Android phone in my pocket these days. BTW - If some kind person can do a PCB design based on Mozzie's scheme (ideally with an SD card reader onboard), I'll get a few made by JCLPCB as a further proof of concept... Regards, IanT |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7471 |
I'm just having a play with a design. I'm wondering if I can fit an audio module on too.... Fairly early days. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 10007 |
https://www.thebackshed.com/forum/ViewTopic.php?TID=17645&PID=233645#233645 https://www.thebackshed.com/forum/ViewTopic.php?TID=17615&PID=232839#232839 |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7471 |
So far...  Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| gadgetjack Senior Member  Joined: 15/07/2016 Location: United StatesPosts: 169 |
I like that design. May try this avenue myself. |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7471 |
I'm not far off now. I've added some GPIO pins and a reset button. Mostly tidying up now. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| mozzie Regular Member Joined: 15/06/2020 Location: AustraliaPosts: 94 |
G'day, A couple more observations The 7" display drags: 0.5A with backlight at MIN 0.9A with backlight at MID 1.5A with backlight at MAX So might be a good idea to power via the USB-C on board. The 5V VBUS is not powered so USB firmware will be a problem. The Waveshare schematic is not much help. The controller on the board is a RTD2281 IanT, Hope you survived the baby sitting adventure... Similar idea to yours, fit a PS2 keyboard and SD card for an all in one MMBasic unit. There is a design in the "to do" list however I cut boards from CAD with an engraving machine (2hr turnaround  ) so hopefully Micks will work for you.Mick, That looks pretty good so far, any chance of a PS2 socket? Regards, Lyle. |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7471 |
PS2 not on board at the moment. You could connect one to the GPIO pins though. I'm not sure I'd want to hang a keyboard cable off the piggyback board. I've just suspended a mini RTC over the top of the uSD card socket. :) I'm picking up 5V from the Waveshare VBUS connection and feeding it into VSYS via a Schottky diode on the Pico. The Waveshare can power the Pico but not vice versa. The Pico can then be programmed using it's own USB connection, which may not be able to supply the current as it's not USB-C. The circuit shows the USB-C VBUS going directly to the Pico VBUS. Not a good arrangement. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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