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Forum Index : Microcontroller and PC projects : 16 colour CMM?
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MicroBlocks Guru  Joined: 12/05/2012 Location: ThailandPosts: 2209 |
I suspect the SPI is the only way to get the pixels out fast enough. What maximum speed would DMA reach when moving data from memory to a port? Microblocks. Build with logic. |
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Nick Guru Joined: 09/06/2011 Location: AustraliaPosts: 512 |
On the topic of memory and what would the real effect with the loss of another 6K would be... On the CMM, my Donut Dilemma game gives the following when the MEMORY command is run. 17kb (21%) Program (844 line) 8kb (10%) 46 Variables 9kb (11%) General 48kb (58%) Free Clearly, I can afford losing 6K to have 16 colour graphics. With the inclusion of many of the new graphics commands, it has allowed code to take up less space. How many other larger programs for the Maximite are there and what do they report? Nick |
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| plasma Guru Joined: 08/04/2012 Location: GermanyPosts: 437 |
Hi , What do you think about the videosystem from the uzebox ? UZEBOX also Vlsi have a cool new chip ? 1 Mbit Versatile SPI / 8-Bit Parallel Bus SRAM ?? mfg |
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| Nick Guru Joined: 09/06/2011 Location: AustraliaPosts: 512 |
Wow. Impressive. And look at all that software (games of course). I don't know C so programming it would be a learning curve, for me at least. That's the beauty of the Maximite, easy to program in interpretive BASIC. I can't emphasise the value of this feature alone. Nick |
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| paceman Guru Joined: 07/10/2011 Location: AustraliaPosts: 1329 |
As I remember, Geoff said that the "framing" capability of the SPI outputs was crucial to getting the video timing right as well and that was fairly unique to the PIC chip. Greg |
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| plasma Guru Joined: 08/04/2012 Location: GermanyPosts: 437 |
yap Nick its right , mmbasic is cool especially with this little chip ;) but i mean uzebox generates 256 colors and have some videomodi, maybe its time to see how it works . Also maybe the 1MBIT ram chip is usesless for the maximite ? But maybe we can work with a second 32 bit pic . ( here a propeller "PC" with some cpu propeller hive ) Connected via spi for the videodata and sound or something ? Maybe someone writes a mmbasic to c translator ? (ala BCX) knowbody knows the future . . |
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Juri74 Senior Member  Joined: 06/02/2012 Location: ItalyPosts: 162 |
this discussion let me think.. if a 480x432 plane does occupy about 26kb (mode 1) why mode 4 occupies the same amount of memory? let me explain mode 4 are 3 bitplanes of 240x216 pixels a plane occupy about (240/8*216) 6.5 kb of memory 6.5 x 3(planes)= about 19.5kb... let's say 20kb.. where are gone the 6 more kb???? |
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Geoffg Guru Joined: 06/06/2011 Location: AustraliaPosts: 3194 |
Hi Juri, Yes, you have put your finger on it. In MODE 4 there is a little over 6KB sitting idle and unused. This is because a single video buffer of about 25KB is permanently allocated when MMBasic is started up and additional buffers are allocated when needed from general memory. The reason for this is to simplify memory management when switching between various display modes. Also, so long as one video buffer is always available, MMBasic will have somewhere to display error messages, etc. In MODE 4 the memory requirement is about 6.5KB per colour so I fitted all three buffers into the permanent buffer leaving an additional 6.5KB unused (as you have noticed). Geoff Geoff Graham - http://geoffg.net |
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| Juri74 Senior Member Joined: 06/02/2012 Location: ItalyPosts: 162 |
hi Geoff oh great! so, are you sayng that if a 16 colours maximite using the sdcard spi and using the half bright trick will be done, that screen mode could occupy the same amount of memory of the mode 4, 8 colours screen mode? impressive... |
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| Nick Guru Joined: 09/06/2011 Location: AustraliaPosts: 512 |
Well that solves the memory issue. What additional circuitry is needed to implement the dual intensity control (16 "colours")? Would this be feasible as an add-on, a Arduino expansion card or new CMM design? Nick |
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9308 |
Well, things have certainly motored along since the OP. I thought 16 colour was well outside of what was possible on the current hardware platform, but now there is a glimmer of light at the end of the tunnel, that it may actually be a possibility with not much change in the circuit either, if I understand things correctly. Assuming all the above, does the PIC32 have the speed to deal with another layer of VGA information? The accelerator pedal is pretty much on the floor now, is it not, going on another members post(I forget who/where, but I remember reading that). Smoke makes things work. When the smoke gets out, it stops! |
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| isochronic Guru Joined: 21/01/2012 Location: AustraliaPosts: 689 |
There are quite a few projects using a QVGA / pic32 combination with impressive results, often using the 16-bit pmp. Google "pic32 qvga" 
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CircuitGizmos Guru Joined: 08/09/2011 Location: United StatesPosts: 1425 |
From what I understand access to the SD card then interrupts the video. Personally I'm OK with 8 colors. I think creeping featurism will hurt acceptance of the product. Micromites and Maximites! - Beginning Maximite |
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djuqa Guru Joined: 23/11/2011 Location: AustraliaPosts: 447 |
I love that term and you are totally correct. First it was Colour, now 16 colours, what is next Full 32bit QVGA @ 2048x1680 Resolution, than 192 core nVidia GPU based addon. Rremember guys, this is a small,simple low cost General purpose controller/educational board/software concept. We are not designing the next iPad or Windows laptop. Plus if you have any specific applications requiring lots of colours/features/power small dedicated PC platform boards are available for very low cost. Or as others have used/suggested, use some of those GRAPHIC oriented boards like the propellor or VGA addon oards. The KISS (keep it smple stupid) methodology is best. VK4MU MicroController Units |
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| CircuitGizmos Guru Joined: 08/09/2011 Location: United StatesPosts: 1425 |
Then you get: > 10 Print "Hello World" > 20 GOTO 10 Error! Out of memory! > Micromites and Maximites! - Beginning Maximite |
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| djuqa Guru Joined: 23/11/2011 Location: AustraliaPosts: 447 |
Exactly! If I need a lot of grunt/graphic power in small form factor Intel makes a Micro-ITX board PC Platform board that is 17cm x 17cm square with ETHERNET/SATA/ 8 USB/VGA/PS2/ 4ch AUDIO/Parallel/2 x RS232 ports and has a 1.8GHZ dual core processor and supports upto 4gb RAM using std DDR3 Dual Channel SO-DIMM modules. And costs under $100 Remember keep everything in perspective. What has been produced already is amazing. Don't kill the golden goose by being greedy. Don't be unhappy with what you have. Be amazed that a small CHEAP board like the Maximite and clones can do so much ALREADY. Plus MMBasic is already becoming a MAJOR development/support headache,so every EXTRA feature is potential New Bugmaker. VK4MU MicroController Units |
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| Nick Guru Joined: 09/06/2011 Location: AustraliaPosts: 512 |
I agree. As it is, it's fine. ... but that extra 8 colours will make games look better! 
Here is a 16 colour (RGBI) image taken from the graphics adventure game off the PC called "Kings Quest"... 
And here is the same image in Maximite 8 Colours... 
The question is, is 16 colours really worth the effort? Nick |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9308 |
I said way back on the first few posts that I figured this was out of the capabilities of the CMM, and that I was perfectly happy with it the way it is, so hopefully you did not read too much into my last post.
I have said it once, and I will say it again - I am perfectly happy with 8 colours. Smoke makes things work. When the smoke gets out, it stops! |
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| Nick Guru Joined: 09/06/2011 Location: AustraliaPosts: 512 |
Maybe 16 colours isn't enough of an enhancement? Maybe it's better to take one of the Arduino shields that offer their own graphics chip with thousands of colours and higher resolution and create a set of libraries to access these? I'm in agreement. 8 colours is plenty for the CMM as it is. Nick |
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| cosmic frog Senior Member Joined: 09/02/2012 Location: United KingdomPosts: 284 |
Does this make any sense to anyone? |
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