FSIO General I/O board has been designed to allow interfacing inputs and outputs to the simulator hardware. Inputs There are 4 input 74LS165 ICs providing total total of 32 inputs available on the board. Input devices (buttons, switches, encoders etc.) can be connected to the board with the use of IDC-10 connectors. Each single IDC-10 socket is connected to 8 inputs on a single chip providing: IC1_OUT – inputs 0 to 7, IC2_OUT – inputs 8-15, IC3_OUT – inputs 16-23 and IC4_OUT – inputs 24-31. REMARK: Although socket names shows _OUT in the name on the silkscreen layer, these are INPUTS and no OUTPUTS here. Descriptions will be corrected to _IN in a future release. Outputs Two MAXIM 7219 LED display drivers ICs are used to control maximum of 16 (8 per single IC) 7 segment displays, each containing 8 LEDs, thus total of 128 LEDs or a combination of both 7-segment displays and LEDs up to 128 LEDs limit (per FSIO-GenIO board). FSIO I/O chain FSIO IN and OUT ports are used to connect multiple FSIO boards into the FSIO chain. How to build the board: The MAXIM display ICs (IC5 and IC6) have to be soldered on the bottom layer side of the PCB. Thus, when building the board, this is important to solder four capacitors: C1, C2, C3 and C4 (which are located between MAXIM pins) on the top side first. Otherwise there will be no way to do it later, when MAXIM chips are soldered in place.