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Forum Index : Microcontroller and PC projects : CMM2 - HDMI and HiRes options
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rrroonn Newbie  Joined: 08/02/2026 Location: AustraliaPosts: 9 |
Hi, Has anyone had experience with running at 1080p on CMM2 Gen2 (or similar)? Does it work reliably in RGB888 or RGB565? Is this with HDMI/DVI or VGA. It seems marginal for the system based on memory bandwidth, so I was interested to how it performs in real-life. I am tinkering with a design that hopes to put out 1080p via HDMI (video only) and trying to understand the real limitations. Thank you in advance! Ron If all else fails, remain flexible and maintain a sense of humour |
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| PhenixRising Guru  Joined: 07/11/2023 Location: United KingdomPosts: 1767 |
I'm also curious because I only have Gen 1. It's frustrating that we get these video modes and it's assumed that users are only interested in low-res retro games and so those are the demos that we get. I am more interested in large, smooth text fonts, etc.  |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 11027 |
Sometimes I wonder why we write manuals  CMM2 manual page 93 |
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| PhenixRising Guru Joined: 07/11/2023 Location: United KingdomPosts: 1767 |
Page 93, read it many times: GUI BITMAP HELP HUMID I2C ????? |
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disco4now Guru Joined: 18/12/2014 Location: AustraliaPosts: 1108 |
MODE command, page 108 the latest beta manual. F4 H7FotSF4xGT |
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| PhenixRising Guru Joined: 07/11/2023 Location: United KingdomPosts: 1767 |
Oh sure but the OP asked: I'm also interested because I only have Gen1 |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 8642 |
The CMM2 Gen2 only can generate VGA at 1920x1080 (Mode 16). This is a HD resolution and VGA is an analogue system unlike HDMI which is digital. The display quality will depend a lot on the VGA connection (i.e. the length and quality of the lead) and the capabilities of the display. The RP2350 in the Pico 2 uses a special on-chip high speed parallel data transmit module called the HSTX to generate the HDMI/DVI signals in hardware. I'm unsure whether anything else would be fast enough to reach 1080P, even the CMM2, so I think you'd be limited to VGA. . Edited 2026-02-17 21:05 by Mixtel90 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: 11027 |
As per the manual 1080P only works in RGB332. This is entirely because of bus bandwidth limitations. 1080P RGB332 has a data rate of 1.19Gbits/second |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 4275 |
Just to fill in about the manual... Colour_Maximite_2_User_Manual.pdf has just one 1080 size: Mode 16 says G2 only It shows only 8-bit for mode 16 and thus RGB332. I hope I've understood the manual :) edit: just saw some more replies as I typed... oh well John Edited 2026-02-17 21:22 by JohnS |
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| PhenixRising Guru Joined: 07/11/2023 Location: United KingdomPosts: 1767 |
Things you'd never expect to read in a BASIC programming manual  |
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| rrroonn Newbie Joined: 08/02/2026 Location: AustraliaPosts: 9 |
Ok, thanks.  If I look at that table long enough (maybe with a lsight squint) I can see where it might seem obvious but its in a table that is talking about pages available in different colour modes, so it did not register. I did spend days looking at doco and code before I asked the question because I don't like asking what appear to be stupid questions, as I know my profile screams "newbie".  Its good to have that confirmation as the hardware manual is not definition, and the basic manual does have it, as you pointed out, but it wasn't clear to me. The code did not make it obvious to me either. Sincerely, thank you. Now looking at the table, it confirm where I got to in my own calculations, that 720p - RGB565 @ 60Hz is doable. My aim is to run that into a TFP410 and out a HDMI port (sans audio), keeping a VGA connector as fallback. Having spent many days seeing how to add the audio in a non-obsolete way was painful and unfulfilling. Most people would say "how hard can it be?" - That was me until I looked at memory bandwidths, pixel clocks, bridge chips, seralizers/deserialisers, what chips can do it, what are available in decent numbers, which are obsolete ... it can actually be hard. I can now stop beating my head against an AI wall trying to come up with ways of squeezing more out of the ole girl. And audio will have to be via another connection, TBD. So, what am I trying to do? Basically, as a keep myself entertained project, I am designing a backplane based boot-to-basic computer using the CMM2 as an inspiration, but with a totally different vibe. The CMM2 is fantastic for what it was designed to be. But I want more. I will post some of my concepts in a follow up post if there is any interest. Thanks again Ron If all else fails, remain flexible and maintain a sense of humour |
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| rrroonn Newbie Joined: 08/02/2026 Location: AustraliaPosts: 9 |
Thanks Mick. If all else fails, remain flexible and maintain a sense of humour |
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| PhenixRising Guru Joined: 07/11/2023 Location: United KingdomPosts: 1767 |
I have been playing with Tassy Jim's demo code on the CMM2 and am liking several modes. I think I prefer the VGA cable due to having screw retainers. The CMM2 can be a serious industrial controller....Instant-on is soooo nice. I come across more and more industrial controllers, running on Windows and what a drag to work with. CMM2 can more than handle these tasks. Just had another encounter with a Beckhoff system with a Windows-7 front-end... nightmare. In-house technicians have no clue where to start with this mess. |
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PeteCotton Guru Joined: 13/08/2020 Location: CanadaPosts: 613 |
Very cool. I have had multiple dives into "creating my own computer" as well. And not for any practical reason - just for amusement/knowledge. It's always good to see what people come up with. One option would be to use the CMM2 purely as a graphics card for your computer backplane. The CMM2 could be controlled via the COM port, keeping it's graphics memory separate, and have it run in parallel with your main processor(s). i.e. You copy image data to the CMM2 from your main processor/memory, and the CMM2 then stores it locally and blits in and out whenever you send it a command string. The CMM2 would be running a custom BASIC program to draw to the screen. You could even use it to drive multiple monitors (one CMM2 per monitor) if you wanted, or make a vertical monitor front end (something I have been toying with as it seems a better aspect ratio for programming). |
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| rrroonn Newbie Joined: 08/02/2026 Location: AustraliaPosts: 9 |
I was originally liking the idea of having a separate "graphics" card and explored a lot of options and came to the conclusion that it is best to put semi-decent graphics on the main MCU card. Any future graphics card will need to be using your "way", it will be a graphics engine with its own VRAM and just get fed instructions like "fill this", "draw that", "set mode xx". And yes, this would allow multiple monitor support. I have SD/MMC buffered over the backplane so decent bandwidth exists for moving bitmaps, etc. Thats now a future stage. I am working on the MCU, power-supply, back-plane and front-panel for stage 1. Edited 2026-02-19 09:56 by rrroonn If all else fails, remain flexible and maintain a sense of humour |
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