Marko Mäkelä wrote: > On Fri, Apr 03, 2009 at 06:23:22PM -0500, Jim Brain wrote: > >> Along those lines, is there a document that describes the tape interface >> from an electrical perspective. My AVR ASM is quite rusty, so the >> C2N232 code is not making much sense to me. >> > > The read, write and sense can be mapped to GPIO. The C2N232 makes use of > the input capture and output compare timer features, but that is not > strictly necessary. It would be good to map CASS WRITE to a pin that can > generate an interrupt. > > The motor voltage is not TTL but something between 6 and 9 volts. In the > C2N232, this voltage is halved by a resistor divider (4k7+4k7 if memory > serves). > > If possible, it could be good to use distinct I/O lines for sense, read and > write on the pass-through port. (Just connect these lines in the AVR > firmware, e.g., by using the Pin Change Interrupt.) If this is not > possible or feasible, you should be able to connect the pass-through port > in parallel. I'm not sure of CASS READ, though. You'd better check the > schematic diagram of a tape drive. > > Marko > > Message was sent through the cbm-hackers mailing list > From - Sun > My apologies for the delay, but I'm jsut now getting to this. Here's my thoughts: http://www.jbrain.com/vicug/gallery/c2npower A simple 'carrier' board that I can immediately use as a power tap, but has through-hole parts, so it can be stuffed by anyone and used for various projects. Now that I've put the schematic up, I realize I probably need to feed MOTOR into the uC (via a voltage divider) so the uC would know when the system is asking for data. Any thoughts? I am trying to balance my immediate need (power tap) with the fact that PCBs cost pretty much the same, regardless of whether there are holes drilled or not. I did not put Xtal or caps on the design, assuming that one could trim the built-in oscillator for satisfactory operation, but I could be persuaded to add them if folks think it would provide a lot of benefit? Jim -- Jim Brain, Brain Innovations (X) email@example.com Dabbling in WWW, Embedded Systems, Old CBM computers, and Good Times! Home: http://www.jbrain.com Message was sent through the cbm-hackers mailing listReceived on 2009-06-29 08:32:02
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