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)