Max Clock input
bigirv
Posts: 37
What is the max clock rate that the prop can run at?· Couldnt i use the ne555 I think that what it is to generate a high speed clock rate?· I understand that high clock rates will cause heat.
Post Edited By Moderator (Paul Baker (Parallax)) : 5/14/2007 11:19:23 PM GMT
Post Edited By Moderator (Paul Baker (Parallax)) : 5/14/2007 11:19:23 PM GMT
Comments
Clock rates up to 96MHz don't generate significant heat. The higher clock rates do require more power.
The NE555 (or other similar timers) are not suitable for high speed clock generation or timing very short intervals. Check the datasheet for specifics since it does vary a bit from manufacturer to manufacturer and from specific model to specific model.
Parallax has done some experiments with pushing the clock rate, including refrigerating the chip to see how fast it could go and what part of the chip·would fail first.· I don't have links to the discussion.· You might try searching the Propeller forum.
Post Edited (Mike Green) : 5/14/2007 11:20:45 PM GMT
Of course we don't provide any warantee that any particular chip is capable of anything beyond 80 MHz.
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Paul Baker
Propeller Applications Engineer
Parallax, Inc.
Post Edited (Paul Baker (Parallax)) : 5/15/2007 12:33:48 AM GMT
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Paul Baker
Propeller Applications Engineer
Parallax, Inc.
Typically the Prop's 8 cogs get divided up amongst various I/O tasks. One does the audio. One does the keyboard and/or mouse. One or more do the video output. There are routines available to do PC compatible I/O to an SD flash card that usually use a cog to do the low level high speed I/O. Each Prop cog is pretty fast so often only one is needed for the main computational task.
You can run several independent video outputs if you want. Each takes one or two cogs and a group of 4 I/O pins. The main limitation is that of memory. There's only 32K bytes total available for the program, its data, and any video buffers needed. The cog's 2K byte memory is too small to hold the video routines and a screen buffer. Some versions store a line of two of video in the cog's memory. That's about all that's available.
You can produce VGA video with the Prop, but, because of the higher resolution and video rate, it takes more cogs to generate it. The minimum is two cogs. There's a 1024x768 resolution driver that handles mixed text and graphics, uses 2 cogs for the video and optionally an additional cog to handle an overlaid cursor. The graphics area is limited by available bitmap video buffer space (in the 32K). Practically, the largest area is 512x384 in 4 colors. VGA also requires a group of 8 I/O pins. I've had programs that used a VGA display and a separate TV display for debugging information.
There is a 512K memory expansion card for the Hydra that's almost finished and is intended for use as a graphics buffer (among other things). There will probably be some new video I/O routines that will take advantage of the extra space to do graphics. I don't believe they're done yet, so it's hard to tell their capabilities.
Because of the small amount of +5V needed (if any), it's generally easiest to use a 6V "wall-wart", preferably a switching type. You use a low-dropout regulator to provide the +5V, then a +3.3V regulator running off the 5V output to produce the +3.3V for the Prop and its support circuitry. The Propeller Protoboard's schematic is available from the Parallax Store's webpage (www.parallax.com/detail.asp?product_id=32212). I'd suggest you just copy the power circuitry.
Because it's a commodity item, the "wall-wart"s are cheap, readily available, and, if from a reputable vendor, reliable. Radio Shack has a nice 6V 1.8A one (#273-1763) that I've used for a number of projects, but there are plenty of other sources and versions. Mouser carries a similar unit.
I take it that you dont know of any thing capable of 3d that i could use with the graphics module?· By modules i am going to design it to where its much like expansion cards in a computer jsut not as fast that way all ud have to do is unplug the video module if it goes out and not have ot buy a new console.· Not that im thinking of sales yet lol.
Is it possible to interface 2 or 3 and make it look like 1 i know ud have to modify the code just curious.· Now as for the sd storage is it better than the compact flash cards?··suchs as this http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=2461770&CatId=376
Mike thanks for your help, I apreciate it.
Post Edited (bigirv) : 5/15/2007 8:19:28 PM GMT
2) 3-D just takes a bunch of memory and processor power. If you really want a 3-D game console, you're probably better off with an embedded PC type unit that takes standard PC graphics accelerator cards or chips.
3) You can't interface several Propellers and make them look like one. The main issue again is memory. It's pretty easy to get them to talk to one another, but dividing up your computational task so they can work together takes a bit of work and only works for some kinds of tasks (where they can mostly work independently).
4) SD cards are much better for the Prop than CF cards because the interface is serial rather than an IDE (parallel) interface as in the CF cards. The SD card interface only uses 4 I/O pins. I'm sure the CF cards need something like 20 or more I/O pins.
For Embedded PCs, you'll just have to search the web. There are lots of vendors. Here's one example: www.arcom.com/pc104-embedded-boards.htm.
http://forums.parallax.com/showthread.php?p=605387
http://forums.parallax.com/showthread.php?p=605385
I found an mps decoder which i will probaly use for the audio module.
if i add ram would u sugest i try to find some ram chips or just use a sperate sd card for my ram...2 gig of ram for the prop would be cool :P but over doing it maybe
The SD card stuff ... It's designed to work in place of a hard disk, not RAM. 2GB may seem like a lot, but it's really cheap. I've seen 1GB cards go for $10 and 2GB cards for $20 and prices are likely to continue to drop.
I really don't think you're going to find any kind of microcontroller designed to do 3D graphics like you seem to want. As I said, this is a major computational task. You will find systems that can run Linux and you should be able to find open source 3D graphics libraries to download and use with it, but you're basically talking about a small desktop system (physically small) with at least a couple of hundred megabytes of RAM and a couple of GB of mass storage (even if it's not a hard disk, but a flash drive). These systems have several megabytes of dedicated video memory and some kind of video accellerator that's directly connected to the video memory and the main processor memory.
The prop is just not there right now. Software 3D, even with really fast CPU's it not generally an interactive experience. You need a dedicated graphics sub-system to do 3D, particularly with textures, lights and effects of any kind, in real time.
Better to get a stripped down PC, maybe a shuttle or one of those micro boards, add a modest 3D graphics card and start building from there. You can still design interesting control interfaces, could use the prop for those even, but the processor core needs to be more complex than micros currently are. (which would make them not micros any more)
If you did this, you could run one of the free DOS systems, Linux, BSD, etc... and craft your own enviornment. The result, apart from the POST test, could be very console like, even sporting carts in the form of flash or USB drives, etc...
One advantage of Linux is support for older, inexpensive 3D cards. A Matrox card, for example, will deliver fantastic 2D along with respectable 3D. Support for OpenGL, SDL, etc... and a configurable boot environment would be inclusive where crafting a game machine is concerned. Building this stuff up from the ground level is gonna be ugly...
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I've moslly bought Propsticks because they're handy to work with on a custom PCB.
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http://forums.parallax.com/showthread.php?p=650217
meow, i have my own topic now? (sorta)
I don't know if you'll be able to do MP3 audio without an external decoder and some kind of external memory (like an SD card) because of the memory and processing requirements. One cog ought to be able to feed an MP3 decoder like the VLSI VS1002 from an SD card, but you'll have to be careful about how the MP3 files are stored. They'll need to all fit in one extent and contiguously so. That way, the I/O routines just need the starting sector number on the SD card and won't need to switch extents which requires additional 512 byte buffers.