The core module is the brain of most projects which are based on the MIDIbox hardware platform. Upcoming applications (which are currently under development) will use the 32bit version.
Main part of this module is the PIC18F452, a microcontroller manufactured by Microchip. It is clocked at 40 MHz (externaly with a 10 MHz crystal) and offers enough performance to handle analog and digital modules with latencies below 1ms. The PIC is a "system on chip" (SoC), this means, it contains not only a CPU, but also an integrated 32k flash program memory, 1536 bytes data memory, 256 bytes data EEPROM, and a lot of usefull peripherals like AD-converter and UART (for MIDI). I decided to use PIC controllers for my MIDI applications many years ago, and I stayed by this product family because of the low prices and worldwide availability for hobbyists. In distance to other (more modern) microcontrollers, the PIC is easy to program, requires no external memories, is almost non-destroyable and comes in a handy DIP package, so that also electronic beginners can work with this chip without the danger of damaging small SMD pins within some seconds with their soldering iron.
If you are planning to program your own application, it's recommended to use a PIC18F452 for highest compatibility with existing MIDIboxes, a PIC18F4620 for RAM intensive projects (64k flash, 1k EEPROM, 3968 bytes RAM), or a PIC18F4685 for code intensive projects (96k flash, 1k EEPROM, but only 3328 bytes RAM - provides CAN interface), or to go for the brand new MBHP_CORE_LPC17module, which gets use of a LPC1769 microcontroller (512k flash, 64k RAM - provides integrated USB interface, Ethernet and much more!).