Leonard@sri-unix (07/23/82)
I have a possible use for a micro, of either the TRS-80 or Apple persuasion, for a scientific application. The choice of which micro I use is highly dependent on which can talk to an A/D converter that is currently available (I have neither the time nor the desire to design my own A/D converter for this application), and on price and programming considerations if such a device is available for both computers. Specifically, I need information about a two-channel A/D converter (one channel may do if I can get one bit of output to control an analog switch to multiplex the A/D input, and more than two channels aren't needed but will be tolerated if the only units come with more), which generates one byte output (either signed or unsigned) in around 50 microseconds or less . The input from the application will be on the order of tenths of microvolts, but I expect to preamplify it to whatever range the A/D converter requires, since I doubt that any available for these computers can handle such low-level signals . I need price, address, phone numbers, and descriptions of A/D hardware for any micro of this sort, and I need to build this thing yesterday. If no such device exists, suppliers of any parallel A/D converter assembly (again, I don't want to have to start from just a chip unless the design time will be very small) and parallel interfaces for either micro would be greatly appreciated. Any other information you throw in about the suitability of either type of computer for this application (how easy it is to interface to, how much equally configured systems including 48K or 64K RAM and two 5.5" drives cost relative to each other) would be appreciated but can probably be obtained through other channels. If anyone can give me some information, my undying gratitude! And thanx much, too! <LNF>
Charlie@sri-unix (07/24/82)
Len, at NYU we are using Apples for a similar applications with two
set-ups - a board set from Interactive Microware in Pa. and a complete
chassis that sits on the Apple from Cyborg in the Boston area; both
seem to do fine but the former is a cheaper way to go and it is less
professionally packaged (and cheaper) than the former. Both of these
suppliers advertise heavily in the magaizines so you should have
little trouble locating them. If you cannot find their phone numbers,
I'll look around. The material is not at easy reach since other labs
are involved. I must plead total ignorance on Radio Shack!
Good luck,
Charlie Strom