Matthew Brush <PICLIST@mitvma.mit.edu> wrote:

> 1. The PIC16F877A hardware UART RX/TX pins will connect directly to
> the MIDI IN/OUT pins through 220 ohm resistors, correct?  I'm
> trying to avoid having to order Optoisolators, so, will the 220 ohm
> resistors be ok?  Also, will I need to invert either of the signals?

    If you're developing your device using a valuable PC as your
    target, optoisolators between your circuit and the soundcard
    would seem to be a lot safer...

    I forget whether the MIDI signal needs to be inverted.

> I'm a little confused because of the whole ASCII thing, but I
> assume that if I putc(0x41), it sends that number out the serial
> port, and if the device on the other end happens to recognize that
> as the ASCII character "A" (like hyperterminal) so be it, but I'm
> still just sending 0x41 out the serial port the same way right?

    Right.  Your 0x41 could be interpreted as ASCII "A", EBCDIC
    no-break space, decimal 65, binary 01000001, or even as a 6502
    "EOR" instruction; it's still 0x41.

    -Andy

=== Andrew Warren -- aiw@cypress.com
=== Principal Design Engineer
=== Cypress Semiconductor Corporation
===
=== Opinions expressed above do not
=== necessarily represent those of
=== Cypress Semiconductor Corporation

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