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Forum Index : Microcontroller and PC projects : PicoMite: I have a nightmare
| Author | Message | ||||
led-bloon Senior Member  Joined: 21/12/2014 Location: AustraliaPosts: 205 |
Thinking inside the box: A PicoMite "dedicated VGA games machine" with the following characteristics. 10 GPIO for VGA 320x240 RGB332 pixel-doubled 256 colour output ONLY. This would require 153.6 KBytes RAM for video frame buffers, leaving 110.4 KB for stack, DMA buffers and program code (anything else?) [GP0 - GP9] 4 GPIO for a "bit-banged" SDCard (or flash file system or both?) [GP10 - GP13] 2 GPIO for audio out [GP14 - GP15] 2 GPIO for serial debug? [GP16 - GP17] 2 GPIO I2C for RTC/networking? [GP18 - GP19] 2 GPIO for PS2 keyboard [GP20 - GP21] 4 GPIO spare [GP22, GP26 - GP28] Suggested pin use in []'s. USB for updates/upgrades/comms (or 5V0 power-pack only) Remove all unnecessary basic interpreter code leaving only core functions. Preset RP2040 CPU speed at 252Mhz - I think ALL picos can achieve this. Move VGA to PIO1 leaving PIO0 free (for now) PicoW for a simplified UDP command input on (default) PIO0? What could possibly go wrong? led Miss you George |
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Mixtel90 Guru  Joined: 05/10/2019 Location: United KingdomPosts: 6814 |
Sounds lovely, I can't wait! Are you going to share the source with us on Github? ;) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 3816 |
Memory may be used more than already posted. Build VGA & W (software) versions, look at MAP files and check? John Edited 2023-03-30 17:09 by JohnS |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 9139 |
Free Memory for program -70kB |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6814 |
I think this should have really been posted on 1st April. ;) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Michal Senior Member Joined: 02/02/2022 Location: PolandPosts: 123 |
ZX SPECTRUM, VIC-20 or ATARI 600XL was enough 16kB or less Michal |
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thwill Guru Joined: 16/09/2019 Location: United KingdomPosts: 4047 |
Hi Michal, Assuming you could find someone to butcher the firmware, who is going to write these games, EDIT: or for that matter play them ? At the moment this community (@Mixtel90 alone) designs a dozen PCBs for every game that gets completed to a (1980s) "publishable" standard. Also the impressive results on those 8-bit machines were (mostly) only achieved through driving the metal directly, and even then in 16K (at least on the ZX Spectrum) the results were not that impressive. If you want to drive the metal of the Pico directly then you don't need Peter and you can have DOOM: https://kilograham.github.io/rp2040-doom/. EDIT: If you want a standard PicoMite VGA configured as a game machine then I point you at @Mixtel90's PicoGAME VGA: https://github.com/thwill1000/pico-game-vga (hosted with permission). Best wishes, Tom Edited 2023-03-30 18:44 by thwill Game*Mite, CMM2 Welcome Tape, Creaky old text adventures |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 3816 |
Yes but you wanted a spec far beyond that. Remove some features from your list. Bare metal, no MMBasic? John Edited 2023-03-30 18:56 by JohnS |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 9139 |
Did you miss the minus sign? -70Kb |
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| Michal Senior Member Joined: 02/02/2022 Location: PolandPosts: 123 |
How to calculate it? Your VideoRAM is only 2 times smaller. Michal |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 9139 |
My video ram is 38400 bytes vs 153.6 KBytes |
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| Volhout Guru Joined: 05/03/2018 Location: NetherlandsPosts: 4256 |
Hi Led, If you are willing to learn VDU codes, you could look at the BBC Basic port on the picomite. Apparently it is running on the pimoroni board. Volhout PicomiteVGA PETSCII ROBOTS |
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| Michal Senior Member Joined: 02/02/2022 Location: PolandPosts: 123 |
Hi matherp, Would using a second Pi Pico as VGA slow down the graphics a lot. Or maybe on the contrary, it could speed up if it was programmed only as a graphics card with predefined primitives? Michal Edited 2023-03-31 00:22 by Michal |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6814 |
But why, for <insert name of Deity here>'s sake? There are far better gaming platforms if that's what you want. Better still, write some games for the PicoMite VGA. After all, you'll have to write your own games for a setup like that anyway. :) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 3816 |
What are you actually wanting? More bits of colour or what? There's already a two-Pico design (a "Pear") where one can be VGA so won't that do? If that won't do whatever it is you want, tweak the design (or do your own) and modify someone's firmware to your heart's content :) John Edited 2023-03-31 01:05 by JohnS |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6814 |
The PicoMite Pear links the two PicoMites (on the same PCB, which can be fitted into an enclosure) using a serial interface. You can use COM, I2C or SPI depending on how you feel. :) Check the link in my sig. Look for PPear Construction Pack. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Michal Senior Member Joined: 02/02/2022 Location: PolandPosts: 123 |
It could have more colors and SDL and relieve the central processor. In addition, the webPicoMite version seems to be heavily overloaded and without VGA. Besides, my question was more about whether there is a method (bus) for very fast communication between two Pi Picos. Maybe by PIO State Machines? Michal Edited 2023-03-31 01:47 by Michal |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 3816 |
Interprocessor comms could be very fast, PIO and/or DMA could help. It's quite an unusual wish so you may have to code it yourself. John |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6814 |
@Michal You could use a Raspberry Pi as the GPU - but then you may as well just put everything on it and save the complication... :) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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