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Forum Index : Microcontroller and PC projects : Picomite VGA Hardware Question
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Rickard5 Guru  Joined: 31/03/2022 Location: United StatesPosts: 463 |
HI I'm working on a New PicoMite Board that will be a compromise of Several Pico Breakout boards, and the Kinda Key thing is, is MMBasic locked to GP21 = Red, GP20 = Green, GP18 = Blue, GP16 = Hsync and GP17 = Vsync? I may be Vulgar, but , while I'm poor, I'm Industrious, Honest, and trustworthy! I Know my Place |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 4044 |
Also GP19 as LSB Green Yes unless you change the source code. John |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7937 |
The pins for the PS/2 keyboard are also fixed. I wouldn't recommend attempting to mess with the source in this case as the pins are being accessed by the PIO as well as the second CPU core, I think. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9610 |
I agree with the above, and so therefore - YES - for all intents and purposes, the pins for VGA(and PS2 keyboard) are fixed and cannot be changed to anything else. Smoke makes things work. When the smoke gets out, it stops! |
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| Rickard5 Guru Joined: 31/03/2022 Location: United StatesPosts: 463 |
WOW that's a BIG BAD BUMMER, now I'll have to Learn C++ to Change the Python VGA Library :( and Grogster you Get a whole Package of Gold Stars with Distinction for proper use of "for all intents and purposes"!!!!! I may be Vulgar, but , while I'm poor, I'm Industrious, Honest, and trustworthy! I Know my Place |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9610 |
LOL!  I worded it that way, cos if you REALLY wanted to, you COULD change the PM-VGA source code to reflect the pins you want to use, but it would be all on your own, and there is basically no official support for any kind of personal port of the source code.  But I fully expect it COULD be done, but would require changing the source, the PIO and the second processor core details to make everything jive on the new pins you want to use, so at the end of the day, most would rule it not worth the effort.  Smoke makes things work. When the smoke gets out, it stops! |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7937 |
No matter how awkward it seems, it's far, far, *FAR* easier to get your PCB layout right than it is to change the source. :) I don't know what you are trying to achieve, Rick, but it's quite possible to get all the signals out pretty easily. I found that they work out remarkably well in most cases. Oh, and changing the python VGA library wouldn't help you in the least on the PicoMite as it doesn't use it. :) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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bigmik Guru Joined: 20/06/2011 Location: AustraliaPosts: 2950 |
Hi Rickard5, Why do you wish to change the pin allocation in the first place? Just curious. Regards, Mick Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<< |
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| Rickard5 Guru Joined: 31/03/2022 Location: United StatesPosts: 463 |
Hi Mick, My Big Plan is to Build one device that can be the EVERYTHING retro machine. I would Really like to run MMBasic, MCUME, or Pythion, and 10000 other things by just reflashing or Swapping out the Pico. I may be Vulgar, but , while I'm poor, I'm Industrious, Honest, and trustworthy! I Know my Place |
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| Rickard5 Guru Joined: 31/03/2022 Location: United StatesPosts: 463 |
Hi Mick, My Big Plan is to Build one device that can be the EVERYTHING retro machine. I would Really like to run MMBasic, MCUME, or Pythion, and 10000 other things by just reflashing or Swapping out the Pico. I may be Vulgar, but , while I'm poor, I'm Industrious, Honest, and trustworthy! I Know my Place |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7937 |
Best of luck with that. :) Whether there's a point when the Pico is probably one of the cheapest parts of the system I don't know. It's been done - it's called a "breadboard". :) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Rickard5 Guru Joined: 31/03/2022 Location: United StatesPosts: 463 |
With all due respect Mick I live in an apartment thew size of Reliant Robin, and right now I Have literally 11 Displays and 5 Keyboards on my Desk, which doubles as my work bench in a room that just happens to also contain a bed that's always in the way, 4 working 3D Printers and a Jewelers Lathe. and Yes I have 4 KVMs! right now I'm Overwhelmed going from a warehouse Living space to a 1 bedroom Apt. and the Idea of one machine with Meltable Personalities like the VM Server I'm putting together to run all my Media is the point. 1 monitor, 1 Keyboard, and 2 joysticks not 12 of each :), the Problem has become so overwhelming, I spent many Hours in the most Evil Place on earth yesterday, I went to IKEA to engineer a solution! Plus I just want to build the most AWESOME Picomite Ever :) I may be Vulgar, but , while I'm poor, I'm Industrious, Honest, and trustworthy! I Know my Place |
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stanleyella Guru Joined: 25/06/2022 Location: United KingdomPosts: 2566 |
I only got one 3d printer and 2 desktop pc's and epson printer in my living room and rpi400 connected to wide screen tv. |
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| Tinine Guru Joined: 30/03/2016 Location: United KingdomPosts: 1646 |
Hey I go to IKEA for the Swedish meatballs (although I never want to know how they're made) Wifey used to have me drive from SE Michigan over to Toronto because it was the nearest IKEA. What a drag...and then i had to assemble the darned stuff  Craig |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7937 |
IIRC the python VGA system is expecting 3 pins per colour plus the syncs. That's 11 pins used. For your idea to work you are going to have to reserve 13 pins (including PS/2 keyboard). The resistor values almost certainly won't be compatible (and you will be mixing the outputs on RGB pins), so you will probably have to reserve a further 4 pins for the PicoMite VGA. 17 pins for just the display and keyboard isn't great.  An alternative way would be to have a pcb with 2 Picos on, one wired for the python library and the other for the Picomite VGA. I've no idea what MCUME uses. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Rickard5 Guru Joined: 31/03/2022 Location: United StatesPosts: 463 |
No Mick now that you explain it, it's not going to work the Python Library is expecting this circuit  I knew I was going to spend a lot of pins on VGA and Keyboard, But I was hoping to make it with 2 picos maybe like the Pico Pair, which is giving me fits right now :( but I do have another Picomite Experimenter system in mind :) Rick I may be Vulgar, but , while I'm poor, I'm Industrious, Honest, and trustworthy! I Know my Place |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7937 |
I'm sure it would be easier with separate boards. You could layer them like hats, but have a single power supply for them all. There's no need to interconnect them and the base area is only the size of one board. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Volhout Guru Joined: 05/03/2018 Location: NetherlandsPosts: 5089 |
The VGA version of the picomite uses many of the pico's GPIO pins (14 of the 24 when you use all options SD/RTC/PS2/audio/VGA) leaving only 10 to play with. I will for some of my projects add I2C IO to expand the IO of the picomite VGA. Probably one or 2 PCF8574's or PCF9574's But the free GPIO's on the VGA picomite are grouped nicely - GP0..GP5 with digital functions, this is a nice group for PIO-1 experiments - GP22 and GP26/27/28 (one digital and the 3 analog pins) is a second group. So a layout looks still simple. Moving pins around may be possible with all but the VGA pins. The VGA pins most likely must be 6 successive pins, since the PIO is designed to work with groups of pins, not so much with individual pins. That is why it is good you realize that the python VGA output uses 8 successive pins for RGB, and that can most likely NOT be mapped onto the picomite VGA pins, or you must redesign the PIO VGA code, and loose access to the remaining 4 pins. Are you sure the python circuit is VGA ? VGA uses HSYNC and VSYNC, not CSYNC. anyway.. Also interesting to note that some pico VGA systems use a I2S audio DAC (not the 44kHz PWM the picomite uses). So making a universal platform will require you to duplicate all these specific hardware differences. Challenging... Although picomite platform has it's specific limitations, it is astonishing so much can be done with a cheap chip. We have to thank Peter and Geoff for that. Edited 2022-10-20 03:10 by Volhout PicomiteVGA PETSCII ROBOTS |
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| Amnesie Guru Joined: 30/06/2020 Location: GermanyPosts: 671 |
Amen!   Always when I look on this forum, I am amazed how much incredible work is done by them, but so does the whole community here. Everyone is so kind and tries it's best to help. I mention this because here in Germany we have pretty much the same (topic) forum (www.mikrocontroller.net) and all I see is bullying and talking in a know-it-all manner. Such a shame... Greetings Daniel |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7937 |
This is remarkably like a group of like-minded individuals nattering in a Back Shed. :) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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