I have opened the case and traced the schematic of the two board. The board 1 and 2 use a flat cable to connect to the main board. all the led on the two boards are connected to SN74HC374 octal D-latch. the microprocessor put the data on all the devices simultaneusly and then activate the clock pin only to the selected devices or the bus structure is this: 8 bits shared between all 5 HC374 5 bits connected each to 1 HC374 clock bit. this for led displaying. (i think that the led are always on or off... no strobing) ah all of the bus bit are tied with a 10k pullup to +5V for the switch, all the switches are grouped by group of eight and are connected like this 1K diode switch +5V ----\/\/\/\/\---->|-----------/___--------- common "read enable" bit of the bus with a 10k pullup to +5V | bit of the bus-----| there are 3 of these "array", one in the board 2 for the foot switches, 1 in the board 1 for the footswitches, and 1 in the board 1 for select/save/ etc etc the tiny button below LED Display. For switch reading I think that the micro pull down the "read enable" bit, read from the bus and check the bit that have a 0 so the bus have another 3 bit for enable the 3 read switch array. I was wondering if the ucapps main module have the required pin for all of this... Is needed an 8 bit port another 8 bit for control (maybe an encoder?? 3 bit to 8????) 5 adc channel for 5 foot controller Serial In/out perhaps.... USB?? I think that I need to develop a custom board that have all "on board and fit the case with all the opening and put midibox inside,,,,, or to leave midios and develop a custom firmware Cheers Nicola Lunghi ps excuse me for my bad english...