Enabling LPC17 MIDI OUT 3 and/or 4

Design Concepts
1

Hi,

 

I’d be interested in having an extra midi out on the MIDIO128, but I’m not sure how to understand the LPC17 core page instructions to bring this about. However if I’m not mistaken it’s not necessary to build an IIC MIDI module.

 

Regarding port J4B the page says:

 

“MIDI OUT4 will be available on the J5B.SA pin, it isn’t required to remove R11 if already soldered - it doesn’t hurt.”

 

However, I don’t see a pin with that name on J5B; only the bottom row has names printed on them, and they are A7, A6, A5, A5, 3.3Vd.

 

Regarding port J5A/B the page says:

 

"And J5B.A6 (MIDI IN3) and J5B.A7 (MIDI OUT3) provide an alternative MIDI IO port as well if “#define MIOS32_UART_NUM 3” has been added to the mios32_config.h file (defines the number of UART ports).

 

So if I add “#define MIOS32_UART_NUM 3” to the config file and then compile & upload, my MIDI OUT 3 pin is at A7..? And that is to be connected to midi out socket’s pin 5, pin 4 to 5VDC (from e.g. J4A, is there a need for an extra resistor?) and pin 2 to ground..? (http://www.midi.org/techspecs/electrispec.php)

 

 

2

Hi,

 

obviously "MIDI OUT4 will be available on the J5B.SA pin" was a typo (fixed), J4B.SA was meant.

 

Anyhow, it seems that you haven’t found this schematic yet, which describes more than 1000 words:

http://www.ucapps.de/mbhp/mbhp_core_lpc17_midi3_midi4_extension.pdf

 

Best Regards, Thorsten.

3

So if I add “#define MIOS32_UART_NUM 3” to the config file and then compile & upload, my MIDI OUT 3 pin is at A7..?

If you are running an unmodified version of Midio128v3, just down load the current release V3.013 which supports 4 Midi ports. Just be sure you also upload the new boot loader at the same time, other wise your USB Midi will not work any more.

4

Thanks to both – success!