I'm producing Midi-Signals through a microcontroller output (5V TTL), which goes into the TTL input of a SAM2695 Midi board.
To assure or control what really is going over the line or arrives at the controller, I would like to sense the signal with a probe connected to the signal and leading into my Mac computer where a program like "pocketmidi" is running. (Anyone knowinga better program, which possibly interprets the hex bytes into corresponding Midi commands?). But in the first place I would like to know what the best method is to adapt the electrical levels accordingly.
To assure or control what really is going over the line or arrives at the controller, I would like to sense the signal with a probe connected to the signal and leading into my Mac computer where a program like "pocketmidi" is running. (Anyone knowinga better program, which possibly interprets the hex bytes into corresponding Midi commands?). But in the first place I would like to know what the best method is to adapt the electrical levels accordingly.
Christoph
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Technical Question — 5 months ago
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The standard circuit uses an NPN or a logic output with 2× 220 Ω.
Using a PNP as a voltage follower is unusual, but will work. The resistors are too small (i.e., the current is too high); use 100 Ω at pin 5 and 220 Ω at pin 4.
Using a PNP as a voltage follower is unusual, but will work. The resistors are too small (i.e., the current is too high); use 100 Ω at pin 5 and 220 Ω at pin 4.
The standard circuit uses an NPN or a logic output with 2× 220 Ω.
Using a PNP as a voltage follower is unusual, but will work. The resistors are too small (i.e., the current is too high); use 100 Ω at pin 5 and 220 Ω at pin 4.
Thanks. Though the circuit is taken directly from the service manual of a musical instrument. Hammond XK1. The same circuit in another Hammond manual uses 220 Ohms from +5V and 120 Ohm to the emitter. Maybe that was an error.
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The XK1 uses a 3.3 V supply. At that voltage, 120 Ω + 22 Ω actually is too much. And the inputs always should use 220 Ω. (The noise filtering is fine, though.)
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