tswift@well.sf.ca.us (Theodore John Swift) (02/20/91)
Please help! I'm trying to attach peripherals (A/D converters, analog multiplexers) to the system bus socket of a Model 100. I have a copy of _Inside the Model 100_, which describes circuits for exclusively input or output buffers/latches, but nothing bidirectional. All my attempts at hooking up a bidirectional buffer (using the read-not, write-not, and chip-select lines) either get no results or latch up the machine. Please reply if you've figured out how to do this, or if you'd like to chat about ideas. -- ---------------------- Ted Swift tswift@well.sf.ca.us "You bally well are informed, Jeeves! Do you know everything?" "I don't know, sir" ~P.G. Wodehouse
bittel@zodiac.rutgers.edu (02/21/91)
In article <23244@well.sf.ca.us>, tswift@well.sf.ca.us (Theodore John Swift) writes: > Please help! I'm trying to attach peripherals (A/D converters, analog > multiplexers) to the system bus socket of a Model 100. I have a copy of > _Inside the Model 100_, which describes circuits for exclusively input > or output buffers/latches, but nothing bidirectional. All my attempts > at hooking up a bidirectional buffer (using the read-not, write-not, and > chip-select lines) either get no results or latch up the machine. > Please reply if you've figured out how to do this, or if you'd like to > chat about ideas. > -- A great way to interface with the 8085 (model 100 microP) is using the Intel 8155 .. (remember to use the CMOS version 81C55).. This chip will interface directly to the bus and has three bidirectional ports!! In fact, a look at the tech man. reveals that this chip is used within the model 100 to drives the display, printer port, etc.. If you need more info Email me.. Hope this helps.. -harry
cameronjames@snoc01.enet.dec.com (James Cameron) (03/05/91)
In article <23244@well.sf.ca.us>, tswift@well.sf.ca.us (Theodore John Swift) writes: >Please help! I'm trying to attach peripherals (A/D converters, analog >multiplexers) to the system bus socket of a Model 100. Me too. I want to make a MIDI interface. I intend to model it on the design published in the MISOSYS Quarterly (V.i) for TRS-80's. I need to know what I/O controller chip I can use to replace the Z80-SIO that that design calls for. The 80C85 processor on the Tandy 102 that I have uses a multiplexed address and data bus. >I have a copy of _Inside the Model 100_ Could you let me know the author and publisher of this work? Have you thought of using a small RS232 UART chip in place of a direct connection? Admittedly it would be an extra few components, but at least it would be compatible with more machinery. -- James Cameron Digital Equipment Corporation (Australia) P/L (cameronjames@snoc01.enet.dec.com)
fzsitvay@techbook.com (Frank Zsitvay) (03/08/91)
In article <1991Mar5.130348@snoc01.enet.dec.com> cameronjames@snoc01.enet.dec.com (James Cameron) writes: >writes: > >Me too. I want to make a MIDI interface. I intend to model it on the design >published in the MISOSYS Quarterly (V.i) for TRS-80's. I need to know what I/O >controller chip I can use to replace the Z80-SIO that that design calls for. >The 80C85 processor on the Tandy 102 that I have uses a multiplexed address and >data bus. well, you have several options. you can still use a z80sio if you demultiplex the address and data busses. or intel may have developed a serial chip designed to work with that processor directly. they did produce a parallel chip, the 8155, that had i/o ports, timers, and other stuff, so there is probably a serial version of it out there. or, use the nsc800 version of the z80sio, which is designed to work with the nsc800 processor (a cmos z80, with enhancements, and designed to look like an 8085) but will work with the 8085 directly, since it can handle a multiplexed bus. -- fzsitvay@techbook.COM - but don't quote me on that.... American Oil Company motto - Bend over, We'll pump!!!
bruceb@informix.com (Bruce Barr) (03/08/91)
In article <1991Mar5.130348@snoc01.enet.dec.com> cameronjames@snoc01.enet.dec.com (James Cameron) writes: >In article <23244@well.sf.ca.us>, tswift@well.sf.ca.us (Theodore John Swift) >writes: >>Please help! I'm trying to attach peripherals (A/D converters, analog >>multiplexers) to the system bus socket of a Model 100. > >Me too. I want to make a MIDI interface. I intend to model it on the design >published in the MISOSYS Quarterly (V.i) for TRS-80's. I need to know what I/O >controller chip I can use to replace the Z80-SIO that that design calls for. >The 80C85 processor on the Tandy 102 that I have uses a multiplexed address and >data bus. > (More deleted) Actually the clock on the built-in serial connector can be software programmed to work as a MIDI port. It isn't exact, but is within the tolerances of the MIDI standards. I read a piece in the Model100 magazine about doing this. Later I mentioned the posibility to a friend I have that is at the Stanford U. Electronic Music Lab. (CARMA) and he ran with the idea! I was out to visit last month and he showed me a small connector, hardley bigger than a 25pin RS-232 connector and the two MIDI sockets. Drew all power from the RS-232 and provided the needed isolation/drivers. He did say that it was mostly just to see if he could do it, and that the software he had developed had pretty much pushed the limits of the machine. Uses it to monitor MIDI signalls and such. Hope this helps. BB P.S. I have no idea how his software development was done. It is worth noting That I sold him an old KIM-1 years ago that he used in converting an old PAIA keyboard to MIDI. Wrote all of the 6502 code by hand. Included and extra 2K of Static Ram he added to get all the features he wanted. His code for the Model 100 might not be pretty, but I bet it's fast...