First, let's get a common board to start the mounting. IMHO, the *hardest* phase of this project was cutting an oldie XT mainboard to get a ISA Slot.

This is the board used for this picnic assembly. The connections are like a proto' board.


Well, this is the ICSP (In Circuit Serial Programming) System of this circuit. The idea here is to separe the wires function by colors - so all orange wires are for programming interface.

Then, lets put the minimal to the system work and talk to the external world. A crystal to give the PIC its clock. A Reset circuit, and a yellow jumper to put the PIC in programming or running mode, or even just resetting the unit. At the bottom we have the serial line interface with a PC. The green wires are for serial data.

A closer look at serial interface circuit. It uses a MAX232 to convert RS232 levels to PIC and the opposite. The 3 pin connector is GND, TX and RX to be connected to a PC. At the left we can see the ICSP interface.


Finally, the basic setup to make a PIC work.


Now, we can connect the cables.



And attach the programmer, to download into the PIC the firmware.


A closer look to our main device - The PIC 16F877

 

Now, the ISA connections:
8 Blue wires: D0-D7 - DATA
10 Brown wires: A0-A10 - Adressing the board
White wire: Interrupt (IRQ4)
Other Blue wires: Signaling






Data and adress lines.