Minimig Shared RS232

By wiring the MCU (PIC18) and the fpga via an AND gate one can eliminate the jumper currently present on the rs232 TxD.

RS-232: Default voltage level is negative (-3 .. -25) = Logical "1"

AND Truth table:
 * {| class="wikitable"

! Input0 !! Input1 !! Output
 * 0 || 0 || 0
 * 0 || 1 || 0
 * 1 || 0 || 0
 * 1 || 1 || 1
 * }
 * 1 || 0 || 0
 * 1 || 1 || 1
 * }
 * }

http://en.wikipedia.org/wiki/Rs232#Voltage_levels http://www.winpicprog.co.uk/pic_tutorial7.htm