routing.txt

The PIC 16F873 is connected this way:

                 +--+---------\/---------+--+
                 | 1|             portb7 |28| <--- Short circuit 2
 LCD data 4 <--> | 2| porta0      portb6 |27| <--- Short circuit 1
 LCD data 5 <--> | 3| porta1      portb5 |26| ---> Enable 2
 LCD data 6 <--> | 4| porta2      portb4 |25| ---> Enable 1
 LCD data 7 <--> | 5| porta3      portb3 |24| ---> DCC signal 2
     LCD RS ---> | 6| porta4      portb2 |23| ---> LED inv 2
    LCD R/W ---> | 7| porta5      portb1 |22| ---> DCC signal 1
                 | 8|             portb0 |21| ---> LED inv 1
                 | 9|                    |20|
                 |10|                    |19|
        Ack ---> |11| portc0      portc7 |18| <--- RS232 RX
 LED misc 1 <--- |12| portc1      portc6 |17| ---> RS232 TX
 LED misc 2 <--- |13| portc2      portc5 |16| ---> LCD E
    I2C SCL <--> |14| portc3      portc4 |15| <---> I2C SDA
                 +--+--------------------+--+