MIDI applications are very timing sensitive (google for "MIDI lag"), and run at about 31K bps. The board supports software serial, but that is basically worthless. Second: there are some unfortunate design flaws on the board. Sparkfun would do well to provide better quality parts for this kit. Mine haven't died on me yet, but I'm just counting the days. Last, the MIDI ports themselves are a cheap, bendy plastic. With a combination of tricks I can squeeze maybe 8 bits out of them. The pots are pretty noisy: this is a problem because for MIDI applications you want at least 7 bits of reliable accuracy, and ideally 10 bits. The provided buttons are really spectacularly bad: from the start they are wobbly and easily mis-trigger, and in my experience they usually start going south after a mere 5000 presses each! Do not install these buttons: buy some better ones. But it has a number of deficiencies, which force me to give it less than a stellar review.įirst off: the parts are low quality. It does just what it says on the tin, and it's easy to assemble and code for. The Shield is unique in providing both an interface (two knobs, three buttons) and a MIDI In/Out, so it's the best option for me. I have purchased a number of Sparkfun MIDI Shields for a project I developed (). The output side should be OK, since there's the 741g125 transmission gate that can perform the 3.3V to 5V stepup, if the 5V line of the shield is indeed powered by 5V from the Due. You can insert a logic translator (or even a resistor divider) there, or cut the VCC trace that leads to pin 8 of the optocoupler, and tie it to the 3.3V rail instead. The concern here is the incoming signal which comes from the optocoupler that is powered by the 5V line: it'll try to drive the RX line to 5V. Applying voltages higher than 3.3V to any I/O pin could damage the board. The maximum voltage that the I/O pins can tolerate is 3.3V. Warning: Unlike most Arduino boards, the Arduino Due board runs at 3.3V. The Due should be providing 5V to the shield, but the documentation states the following: Update: I just took a closer look at things. Since the LED in the input port is part of the sender's current loop circuit, the 220
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