Midipipe manual update#
Because of the complexity of what I want to do, it is far easier to go thru the entire MIDI note table and update all notes for the board for each received note. Unification will not be a problem since it is inherent in the design.
Midipipe manual how to#
Most of my thought has gone into how to handle the stop control and receiving the note data. I haven’t put any though into any couplers but it might be simple to add.
I could have gotten a better price if more boards were ordered.
Very pleased with he quality and the speed. What a deal! It took less than 9 days for the boards to come it. I ordered 10 double sided boards, 14 X 4.5 inches with green solder mask and component silkscreen for $43.00 per board. I have already created a board layout using a free software package by Express PCB ( The software has a schematic drawing package that you can import into the PCB layout software for helping out with laying out the PCB. And they don’t completely do what I want either. I know that there are other MIDI driver boards but I just don’t want to pay $200+ per board. I am taking extra precaution in the software to set the output registers HIGH before setting the port control registers which defines the port as an OUTPUT line. The only problem might be internal to the driver chip. I tied a 10K resister to +5 so it will be pulled up when power is applied. The TPIC6B595 has an output enable pin that when high, turns off the outputs. I am taking extra precautions to make sure that the outputs don’t get enabled during power up of the board.
Midipipe manual serial#
To connect 2 or more boards together, you connect a MIDI cable to the first board and then use the output signal from the PC900 to send the serial data to the other driver boards. The board will receive the MIDI serial data from these 2 wires only. I think they come into play at about 40 or 50 volts.Īs far as buffering the PIC from the organ, I am using a PC900 optic-isolator. These are active clamps rather than just diodes. The chip even has clamp logic for driving coils directly. 25A when all outputs are turned ON at the same time. 5A per output but when you read between the lines, it can only support. The specification says that it will support. You can shift the data into the shift register and then transfer the shift register data into the latches, all being in a 20 pin DIP package. This chip has 8 driver outputs, with an 8-bit shift register and 8 data latches. You can go to and get the specifications. This would be the common high side configuration only. I plan on using a driver chip that I think only comes with current sink capability. The startup defgault states need to be correct so that all magnets are not triggered before the initilization is complete.Īt this time I haven’t thought about trying to support common ground or common high side magnet configurations.
Midipipe manual drivers#
You need to be able to handle the magnet transients.Īnother consideration that is often overlooked is the sequence of power application to make sure the drivers are protected when either the magnet power is turned on before the processor initializes the outputs. High side driver devices are rarer than low side driver chips. hence a general purpose driver needs to accomodate both high side and low side drive of either polarity.Īny connections from the PIC to the organ should be WELL buffered to prevent noise and transients that could disturb or destroy the processor.įrankly, I would consider having the driver board separate from the processor board and have versions to accomodate the polarity variations I mentioned. It seems simple to just change power supply polarity for a driver BUT often there are steering and transient diodes already in the system which preclude doing this. Sometimes the organs have common grounds and sometimes common high sides. Re: MIDI Pipe organ driver board design ideasĪ couple of thoughts from this electrical engineer.
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