The IIC MIDI module provides a bridge between IIC and MIDI, and mainly consists of a PIC16F88 microcontroller from Microchip, which runs with a special firmware (not MIOS!).

IIC and MIDI are both serial interfaces:

• IIC (Inter-IC, the abbreviation "I2C" is oftenly used as well) is qualified for fast data exchange between multiple devices via a single clock and data line
• MIDI (Musical Instrument Digital Interface) is the asynchrous interface you propably know very well (otherwise you wouldn't be interested in this site ;-)

Combining these two interfaces opens the possibility to access multiple MIDI In and Out ports from a single microcontroller. In addition, the IIC MIDI "slaves" are doing some high level MIDI protocol handling in order to relieve the "master" core from time and memory intensive tasks. This improves the overall performance.

The firmware has been prepared for up to 4 IIC MIDI slaves connected via the IIC bus to a single master:

A simplified interconnection diagram:

Imortant note for MBHP_CORE_V2 users: an additional 1k pull-up resistor is required between the Vd and SC line, it has to be directly soldered at CORE::J4 in order to allow "clock stretching". Thats a method to delay serial transfers when a slave cannot response immediately on a master request. The pull-up resistor for the SD line is already available at the core module (CORE::R2).
MBHP_CORE_V3 users will notice, that both pull-up resistors are already available - no additional resistor needs to be added!