Hi,
I am using the C5535 eZdsp, and after doing processing on some input audio signal, I would like to output a digital MIDI signal from the board. MIDI is a digital communication protocol used for communication between electrical instruments. I am wondering what module in the C5535 I should use to output MIDI.
The MIDI specification is defined as:
MIDI messages are made up of 8-bit words, and are transmitted serially at a rate of 31.25 kbaud. The first bit of each word identifies whether the word is a status byte or a data byte, and is followed by seven bits of information. A start bit and a stop bit are added to each byte, so a MIDI byte requires ten bits for transmission, of which only seven contain MIDI data.
At the physical layer:
Logic 1 → High → no current flow → Opto-isolator LED off → MIDI receiver sees High, logic '1' (data bits, stop bit or idle)
Logic 0 → Low → current loop flow → Opto-isolator LED on → MIDI receiver sees Low, logic '0' (data bits, start bit)
It seems like the three choices that would be possible are GPIO, UART, or SPI. SPI is used to program EEPROM though, so I don't think that SPI is the correct module to use.
Any help is appreciated!
Thanks,
Nate