secrist@msdsws.DEC.COM ("Richard C. Secrist") (03/14/89)
I believe there was an article in Byte circa 1984/5 on making your Apple into a o-scope. I just moved so it'll be some time before I could find it, but you can try the Guide to Periodical Literature at your local library or a Byte index. If I find it sometime I'll post the info here. rcs
DANFUZZ@BROWNVM.BITNET (Dan Bornstein) (03/15/89)
If you are wondering about an oscilloscope for the IIgs, I wrote and released one called "AFOSC" a year or so ago. It went out on a local bbs and purportedly got to some others nationally. I've never actually uploaded to the net, and only have a 300 baud modem (ugh! Thank goodness I get to use campus (almost-direct-connect) computers most of the time, but they're all Macs...), but if there's enough interest, I'll try to put it on apple2-l or wherever it is that I'm supposed to stick binaries. -dan
dr@skivs.UUCP (David Robins) (03/16/89)
In article <8903141523.AA10294@decwrl.dec.com> secrist@msdsws.DEC.COM ("Richard C. Secrist") writes: > > I believe there was an article in Byte circa 1984/5 on making > your Apple into a o-scope. I just moved so it'll be some time The article was in 2 parts: Putting the Apple II to Work Part 1: The Hardware Richard Hallgren Michigan State University Byte April 1984, pp. 152-164 Putting the Apple II to Work Part 2: The Software Byte May 1984, pp. 382-396 Note that this does not display data in real time, like an oscilloscope, but rather like the digital computer modules that turn computers into scopes which first digitize, then display the data. Their assembly language display is 40-50x faster than HPLOT. The article claims that graphing an array of 1000 points from within a BASIC program takes about 0.4 seconds. Therefore, they acquire data in epochs, interleaving the display between epochs every 1 to 3 seconds. To display in real time means you are limited by the speed of an assembly language routine to acquire the data, the display it on the Apple scrren, using the ROM routines (slow) or doing your own addressing (faster). (ref: Fast Graphics of the Apple II: A Machine Language Utility with Laboratory Applications, in Instruments & Computer, Jan/Feb 1986, pp. 7-11.) The fastest display is using special hardware to handle the display. Dataq Instruments used to make a card called the Waveform Scroller, which was discontinued a few years ago due to lack of sales. I cost about $700, and let you display up to 8 channels. It did real-time scrolling - the waveform traveled across the screen, left to right or right to left, like a stripchart. Very good for up to 500 points per second. At higher rates, one used their oscilloscope mode, which had retrace and triggering, like an oscilloscope. It could do up to 3000 points per second on a standard Apple. Using an accelerator card to speed up the software driver, I got significantly higher rates (I think up to about 7000 points/sec.) I was one of only 4 buyers of this card in the country, and I still use it to display eye movement data in real time. I can also playback data, and pipe it through the card. If there is enough interest (> 12 orders), they may revive this card. It is still being made for the IBM, a much larger market, in part due to the fact that they have menu driver CODAS software for the IBM. The Apple version had a driver, which could be called from Applesoft or assembly language. I wrote my data acquisition routine in assembly, because I took in 2 12-bit readings every 5 milliseconds ( 2 channels at 200 Hz. each). -- David Robins, M.D. (ophthalmologist / electronics engineer) The Smith-Kettlewell Institute of Visual Science, *** net: uunet!skivs!dr 2232 Webster St, San Francisco CA 94115 *** 415/561-1705 (voice) The opinions expressed herein do not reflect the opinion of the Institute!