paravia@csd4.milw.wisc.edu (Mark David Kakatsch) (02/11/89)
Hello. First off, I'd like it if Roger Hascomb would contact me. I've seem to have lost your net address. About my S-100 system, It SEEMS to be working, but I am not sure. It's generating the signals that it is supposed to, however, they aren't exactly square waves. It's more of a sine/triangle wave. I have NO idea why this happens, as I am using all the values listed for a 2 Mhz. system, and the 8224 clock chip checks out ok. The only way I can really find out if it is working is with an Imsai type front panel. Are there any companies that still sell kits of those? Oh, it DOES, however, turn off the lights on the parallel board when I install a test ROM that SHOULD make them flash. Ack. Well, I asked for it... Mark +-----------------------------------------------------------------------------+ + Things are not what |Albert Einstien got his name after he got smashed + + they appear to be... |after drinking one stien of beer. Hence; Albert + +________________________|EinStien.___________________________________________+ + Ack! Ack! Ack! Ack! Ack! |Mark D. Kakatsch --> paravia@csd4.milw.wisc.edu + + Pfhtph! Pfhtpph! Pfhtpf! | uwmcsd1!uwmcsd4!paravia + +-----------------------------------------------------------------------------+
cook@stout.ucar.edu (Forrest Cook) (02/15/89)
In article <885@csd4.milw.wisc.edu> paravia@csd4.milw.wisc.edu (Mark David Kakatsch) writes: > About my S-100 system, It SEEMS to be working, but I am not sure. It's >generating the signals that it is supposed to, however, they aren't exactly >square waves. It's more of a sine/triangle wave. ... >is with an Imsai type front panel. AAACK PHTHTHT You said that word, IMSAI! I have an old Imsai and the reason your bus has non-square waves is probably due to the fact that the front panel's LEDs are connected directly to the bus with NO buffering. Who did that anyway? If you want to make the thing work much more reliably, kludge in some octal buffer chips between the bus and the LEDs. While you are at it, it might not hurt to cut the power switch traces that run about 1/4" from a bunch of one-shots and run the AC right to the switch. 220/330 ohm terminator resistors on all of the bus lines will also clean up the signals. Remember the front panel will only work with CPU cards that have the CPU data bus availible on a 16 pin socket, and port FF is used by the front panel data in/out port so beware of address conflicts. Remember, you can buy a NEW 10Mhz XT clone with 640K and 30Mb of hard disk for $1200 if you shop around. There is a public domain? program called Z80MU that will allow you to run your old CP/M software if you must. I use that setup on a 386 to cross compile Aztek C for Z-80 boxes. The 20 Mhz 386 can emulate a 2.1 Mhz Z-80, WOW :-) ^ Forrest Cook (The preceding comments were my Opinions) ^ /|\ cook@stout.ucar.edu /|\ /|\ {husc6 | rutgers | ames | gatech}!ncar!stout!cook /|\ /|\ {uunet | ucbvax | allegra | cbosgd}!nbires!ncar!stout!cook /|\
paravia@csd4.milw.wisc.edu (Mark David Kakatsch) (02/15/89)
In article <1407@ncar.ucar.edu> cook@stout.UCAR.EDU (Forrest Cook) writes: > >I have an old Imsai and the reason your bus has non-square waves is probably >due to the fact that the front panel's LEDs are connected directly to the >bus with NO buffering. Who did that anyway? If you want to make the thing >work much more reliably, kludge in some octal buffer chips between the >bus and the LEDs. While you are at it, it might not hurt to cut the power >switch traces that run about 1/4" from a bunch of one-shots and run the AC >right to the switch. 220/330 ohm terminator resistors on all of the bus >lines will also clean up the signals. >Remember the front panel will only work with CPU cards that have the CPU >data bus availible on a 16 pin socket, and port FF is used by the front >panel data in/out port so beware of address conflicts. etc... Those are some good suggestions, however, I get a triangle wave even when the front panel is not connected, and I run a little program that loops to itself in ROM...It doesn't, however, seem to affect the operation of the board, as it DOES work...Just wish I could get those damn drives going... Mark +-----------------------------------------------------------------------------+ + Things are not what |Albert Einstien got his name after he got smashed + + they appear to be... |after drinking one stien of beer. Hence; Albert + +________________________|EinStien.___________________________________________+ + Ack! Ack! Ack! Ack! Ack! |Mark D. Kakatsch --> paravia@csd4.milw.wisc.edu + + Pfhtph! Pfhtpph! Pfhtpf! | uwmcsd1!uwmcsd4!paravia + +-----------------------------------------------------------------------------+