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Forum Index : Microcontroller and PC projects : colours - colour table - bit per pixel
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| hhtg1968 Senior Member  Joined: 25/05/2023 Location: GermanyPosts: 123 |
Hello (perhaps mainly to matherp or geoffg)! since yesterday i can program on my picomite. many thanks... a few questions: 1. if i test the colours by typing "colour rgb(...)" (blue, cobalt etc.) i see only 8 colours (every colour twice). is this my mistake? i could send a foto... 2. is there kind of a colour table/ map? i want to access to the colours by a number (0-15) in a game. otherwise i have to create an array with the rgb numbers... 3. in mode 2 there are 4 bits per pixel. does this relate to the speed of the dma/pio or is this an artificial limit? i think it makes not a big differencei if you have a screen memory/ buffer of 38kb or 76kb... 8bit/ 256 coloura would be nice. but i am so happy to have this small machine with (only) 16 colours... yours hhtg |
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phil99 Guru  Joined: 11/02/2018 Location: AustraliaPosts: 2137 |
That is consistent with one of the 4 outputs (GP18 - GP21) not connecting to the VGA socket. If the 8 colours you see match the names it is probably the GreenLow (GP19) that is missing. Check for a bad connection. To test each pin copy & paste each of these lines to the console:- CLS RGB(255,0,0) 'red GP21 CLS RGB(0,0,255) 'blue GP18 CLS RGB(0,64,0) 'dark green GP19 CLS RGB(0,128,0) 'mid green GP20 CLS RGB(0,255,0) 'bright green GP19 and GP20 Edited 2023-06-14 16:50 by phil99 |
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| Volhout Guru Joined: 05/03/2018 Location: NetherlandsPosts: 4247 |
Check your wiring.... There are 4 pico pinns that drive the VGA, check resistor values and wires...  Edited 2023-06-14 17:09 by Volhout PicomiteVGA PETSCII ROBOTS |
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IanRogers Senior Member Joined: 09/12/2022 Location: United KingdomPosts: 151 |
I just tested my new set up. version 5.0707 VGA All 16 are present ( 3 shades of green as per above ) I'd give my left arm to be ambidextrous |
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| hhtg1968 Senior Member Joined: 25/05/2023 Location: GermanyPosts: 123 |
many thanks to you all. now it works!!!! i placed the wire for 1/3 green wrong (1 cell). i need glasses but often i do not wear them... and i am not a hardware specialist, so i had to ask you... |
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| IanRogers Senior Member Joined: 09/12/2022 Location: United KingdomPosts: 151 |
Welcome to our world.. I have about 6 different pairs each for their own focal point. Driving Gaming general use Electronics 2 pairs one set with built in magnifiers. You may still have a way to go... I'd give my left arm to be ambidextrous |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
@ hhtg There are no "colour numbers" on the PicoMite. If you want them you have to create your own. There are various ways to do this. I usually use an array: DIM C(5)=(RGB(black),RGB(blue),RGB(myrtle),RGB(cobalt),RGB(midgreen),RGB(cerulean)) or whatever colours I happen to need at the time. Then I just use C(0) instead of typing RGB(black) or RGB(0,0,0) You can use any of the colours in any order you want, of course. You don't need to set up the array to use them all either. There are cleverer ways to do this, and to stuff the array, but this is all I usually need. It saves a lot of typing too. :) Edited 2023-06-14 19:53 by Mixtel90 Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| hhtg1968 Senior Member Joined: 25/05/2023 Location: GermanyPosts: 123 |
thanks. ok. i use an array but i wanted to know wether it is more easy... a colour with a "number" has advantages. you can change the colour in a tabel and the change applies for all such collours in the screen. |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
That was why I started using an array. Well, that and the typing 'cos I'm lazy and don't touch-type. :) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2137 |
You could use the 24 bit integer values, though it isn't really practical. Red Green Blue 24 bit value 0 0 0 0 0 0 255 255 0 64 0 16384 0 64 255 16639 0 128 0 32768 0 128 255 33023 0 255 0 65280 0 255 255 65535 255 0 0 16711680 255 0 255 16711935 255 64 0 16728064 255 64 255 16728319 255 128 0 16744448 255 128 255 16744703 255 255 0 16776960 255 255 255 16777215 |
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| hhtg1968 Senior Member Joined: 25/05/2023 Location: GermanyPosts: 123 |
what happens when you take other values? are these 16 colours fix? |
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| phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2137 |
Those are what is set in the firmware. If you enter any other numbers you just get the colour of one in the list of 16. Eg CLS 155 is the same as CLS 255 To get any other colours requires changing the hardware between the Pico and the VGA socket. Edit Will post about doing that with plug-in modules in a few days. Edited 2023-06-14 23:11 by phil99 |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 3804 |
You'll get whatever the hardware does and probably make your code harder to understand or change. Yes, unless you change to non-standard Picomite hardware. Probably best to stick to the colour names (at least in the array if you use it) and I suspect porting to another MMBasic platform (such as MMB4W) may be easier. John |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
The PicoMite doesn't actually know anything about colours. It simply stores a 4-bit number to represent a colour then outputs that number direct to the VGA colour pins at the right time. After that you can do what you want with the numbers. The colour names are only their to be friendly. Peter has chosen to use the 4 bits as RGB 1-2-1, so 1 bit each for red and blue and two bits for green. You could equally use 2 bits for red, 2 bits for blue and green fixed at 10% (RGB 2-0-2), giving you 3 shades and off for red & blue and a seriously weird display where dark green is the new black! You would still have 16 colours but it would mess the colour names up, of course. :) You could equally well have 16 green levels by messing with the resistors. You can never have more than 16 colours on screen at once, as there are only 4 bits, even if you use some sort of system to switch the VGA resistor network. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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stanleyella Guru Joined: 25/06/2022 Location: United KingdomPosts: 2129 |
I got this from the forum 'colour shortcuts const WH =RGB(255, 255, 255) 'WHITE const YE =RGB(255, 255, 0) 'YELLOW const LI =RGB(255, 128, 255) 'LILAC const BR =RGB(255, 128, 0) 'BROWN const FU =RGB(255, 64, 255) 'FUCHSIA const RU =RGB(255, 64, 0) 'RUST const MA =RGB(255, 0, 255) 'MAGENTA const RE =RGB(255, 0, 0) 'RED const CY =RGB(0, 255, 255) 'CYAN const GR =RGB(0, 255, 0) 'GREEN const CE =RGB(0, 128, 255) 'CERULEAN const MI =RGB(0, 128, 0) 'MIDGREEN const CO =RGB(0, 64, 255) 'COBALT const MY =RGB(0, 64, 0) 'MYRTLE const BL =RGB(0, 0, 255) 'BLUE const Bk =RGB(0, 0, 0) 'BLACK const Gy =RGB(128, 128, 128) 'GREY const Lg =RGB(210, 210, 210) 'LITEGREY const Og =RGB(255, 165, 0) 'ORANGE const PK =RGB(255, 160, 171) 'PINK const Gd =RGB(255, 215, 0) 'GOLD const SA =RGB(250, 128, 114) 'SALMON const BE =RGB(245, 245, 220) 'BEIGE |
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| hhtg1968 Senior Member Joined: 25/05/2023 Location: GermanyPosts: 123 |
i understand the bitmaps in combination with the number of bit per pixel. i often wrote scroll routines, bitwise etc. but i don not have any knowledge of vga hardware. i hope my questions are not to dumb... to stanleyella: you list more than 16 colours. i will try further... |
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| hhtg1968 Senior Member Joined: 25/05/2023 Location: GermanyPosts: 123 |
the picomite basic knows the "keywords" for gold, grey etc. (more than 16 colour names), but hardware forces to similar colours... gold is yellow... |
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| stanleyella Guru Joined: 25/06/2022 Location: United KingdomPosts: 2129 |
you can only use any 16 at once. |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
@ Stan Those colours will not work for the PicoMite as they are not RGB 1-2-1. You can't get values of 210, 165, 160, 114 and 220 on a PicoMite. They don't seem to tie in with the CMM2 either. It's not a case of *choosing* any 16 at once, you have no choice. You get a single 4-bit number and that's it. That's 16 values. The "colour lookup table" is the resistor network between the PicoMite pins and the VGA socket. :) Any colour names that refer to the same colour are to help with compatibility between platforms, that's all. Edited 2023-06-15 04:07 by Mixtel90 Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| stanleyella Guru Joined: 25/06/2022 Location: United KingdomPosts: 2129 |
All good info Mick. me Doh! I got the constants from the forum and no error message using but then I only use a few colours from the 8 "primary" colours. just when I think I'm understanding mmbasic I realize I don't :( Just going back to vga from using lcd and it's fun with a "big" display though 320x240 16 colours is the same. using a ps2 keyboard and a lcd seemed silly |
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