MIDI Sync Box

Posted on Feb 6, 2014

Everything works just great. The final software is 930 lines of assembler. I also learnt how to use ProTel so I could draw up the final circuit properly. Here`s the result. Notice that I`ve got it down to just one chip now, the little PIC is doing everything. It can directly drive the LED and the MIDI output. I`ve used multiplexing to enable it to drive the 7 segment display and read all the inputs. The PIC`s built in timer keeps

MIDI Sync Box
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everything running accurately, all in all, I`m very pleased with the result. Since I last did any work on this project, I have upgraded my PC to a Duron 900 and have installed Windows 2000. I am most impressed with the stability of Win2K, I rarely have more than two crashes per week as opposed to about three times a day under Win98. However, Windows 2000 will not run the NOPPP software which I have been using to download code into the PIC. I suspect the way ports are accessed in Win2K is not backward compatible with Win95. To cut a long story short, I have found the Linux version of NOPPP works just fine so I`m using that instead. gpasm is a free compiler for the PIC which runs on Linux so I`m all set to continue development without using Windows. I`ve redesigned the thing again and got rid of the buffer chip. I`m driving the MIDI output directly from the PIC and it works fine. I`ve used a 7 bit bus arrangement to allow all the inputs to share the same I/O pins as the LED display. One little hitch was the discovery that the big red illuminated push button needs 12 volts to light up. But I`m running everything off 5 volts. So I`ve made a little adapter out of a small piece of veroboard so I can substitute a LED. I tellya these modern LEDs are so bright! I nearly blinded myself messing about with it. One thing I had a lot of trouble with was understanding the MIDI signals. I couldn`t seem to find much documentation on them....

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