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MarkS

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  1. The Prop doesn't use interrupts, BUT by monitoring the clear pin on the shift register I could fake it. I need to start prototyping. Something tells me this will be easier than I think, but I'm going to have to be a little more clever than I'm being.
  2. I can. The issue is the strange frequency. Most microcontrollers and processors are made today to use a evenly divisible clock frequency. I want to use the Propeller because it have built in video generation, but it works best with a 80 MHz clock (delivered via an external 5 MHz source clock and its internal PLL). Since there is an unique pixel on the video line at each clock pulse, I cannot simply read the video signal and act upon it. 0100011100000 would look like this to the Prop: 01010. Clearly not the correct pixel data. This means that I must run the prop at the 15.6672 frequency and tes
  3. The video rate would be the reason to do this. Getting it from 15.6677 to 16 MHz would make it much easier to read. Nothing now runs off such an odd frequency and reading any data clocked off of that frequency presents some rather difficult challenges. But hey, Apple saved a buck or two on a baud frequency generator!
  4. The logic board has circuitry that divides the clock signal in half. I would need to supply a 16MHz clock to the logic board in order to run the processor at 8 MHz.
  5. I hate to bring this back up, but I have a couple of questions I hope can be answered. Since the frequency is related to baud rates and the serial ports are really all but useless now (at least for me anyway), what other effects would I see by bumping up the frequency? My biggest concern is screwing up the RTC. Would bumping it up to 8 MHz cause any sort of stability issues?
  6. It's really strange. My dad bought me that computer in '92 or '93. I haven't used it since around 2000. I bought an iMac in '98 and the iMac's IDE drive is toast.
  7. It works! It arrived today. I was able to get all of the information off of the drive, including a game that my dad was working on that I lost many years ago. I'm in more of a state of shock right now than happy. I never thought I'd see this stuff again!
  8. Propeller God? No. I've done one project with the Prop, a temperature controller for a reptile enclosure. It used a 4x20 character LCD and I had to write the driver for that. What surprised me was how easy everything was. It helps that Parallax has excellent documentation and a busy support forum. I'm looking at this as a challenge. Heck, if I wanted to go the easy route, I'd just fix the analog board. I expect to hit some walls, but that's no problem. This will be fun.
  9. I'm probably going to have to grab the whole frame. The scan doubling sounds interesting, but it will be displayed on an LCD monitor. What I think I'm going to do is make the bitmap 1024x768, double the video input and center it vertically in the bitmap. This shouldn't be too hard and I'll need to add extra memory anyway, so that's not an issue. I'll just plot two pixels instead of one and plot two scanlines at a time. This will double the resolution which will be necessary anyway (512x342 is tiny on a large monitor) and make the bitmap a resolution that is more or less standard. Compatibility
  10. Sorry, I was writing my post while you made your post. Taking the signal off the board is an option, but then the two boards are physically locked together. I really don't want to do this if I can avoid it. The video processing on the Prop will be in software. I'll read read the H Sync, V Sync and video signal with three of the Prop's I/O pins. The actually processing will be going on inside the Prop. Essentially what I'll be doing is turning the Prop into an oscilloscope. The software will be reading the video input pins at a higher frequency than the Mac provides and acting appropriately whe
  11. Oscillators with a 7.8336 frequency and its multiples are extremely hard to find. I found a 31.3344 MHz oscillator and will run the Prop off of that. I'l use the Prop's built-in PLL to double this frequency to 62.6688. The software written for the Prop is typically designed to work at or near 80 MHz. There is plenty of example code (called Objects) in the Propeller Object Library that will greatly simplify the coding of this. Not that the coding would be all that hard anyway. I'm also adding a USB keyboard to Mac keyboard converter as well as a USB mouse to Mac mouse converter. Each of those c
  12. Everything derives from the same clock. The frequency from the oscillator is divided in half for the processor and further for other IC's. The full clock speed is fed to the video generator. I would imagine that everything would scale to the newer clock. What was the reason behind the odd clock speed?
  13. I am working on a project with my Plus. The analog board is dead and while I do plan to fix it, I want to play around with a microcontroller. Anyway, One thing I'll need the microcontroller to do is read the video signal and convert the data to a VGA signal. I'm going to be using the Parallax Propeller microcontroller and it can generate a VGA signal natively. However, while doing research, I found that the video signal is 15.6672 MHz (the frequency of the oscillator). While the propeller runs at 80 MHz, sampling an odd frequency will be difficult, if not impossible. I can change the oscillato
  14. I found that earlier, but wans't sure which to download. I'm dual booting XP 32-bit and Windows 7 64-bit. I'm thinking the Vista drivers might work with 7. Windows' generic drivers might work as well. Of course, the card may come with the drivers. I'll soon see...
  15. This is it here: http://cgi.ebay.com/IBM-10L7095-Adaptec-AHA-2940U-W-B-SCSI-Controller_W0QQitemZ390112599170QQcategoryZ56092QQcmdZViewItemQQ_trksidZp4340.m263QQ_trkparmsZalgo%3DSIC%26its%3DI%252BC%26itu%3DUCI%252BIA%252BUA%252BFICS%252BUFI%26otn%3D10%26ps%3D63#ht_3106wt_1165
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