Hi ,
Just wondering if anyone has any ideas on how to improve on this
input/output circuit. Using 2 I/Os (RB0 and RB1 on a 16C505) I am trying
to drive two back to back LEDs and read a switch at the end of  2 long
wires: Here is some bad ascii art.  The function is as follows:

RB0      RB1    GREEN       RED
1            0           ON            OFF
0             1           OFF            ON
0           INPUT ( CHECK SWITCH)

The wire I am driving(reading) is quite long approx. 300 ft. I am having
troubles reading the switch.I can read the switch ok if  I don't change
RB1  to an output . But thats no good because I have to be able to
switch the LEDs.I tried putting nops between my TRIS statements etc. A
code snippet is below  If anyone has any suggestions I'd be grateful
ie.

LED1                     (Red, Green and 10K in parallel)
                                                                -
|<|---- (Red)
                470 ohm            long wire         |           |
RB0 ----/\/\/\/\----o    o-------------------- -|>|----   LED2 (Green)
                            |
|             |

-/\/\/\/-------0  (shorts RB0  to RB1 when ON)
                          _|__                                 10K
ohm       /o SPST switch
                          ___  .01
uF                                           |
                             |
GND                                         |



|
100K
|
        _/\/\/\/----+5
Volts                                                   |

|
|
        |     470 ohm             long
wire                                  |
RB1 ----/\/\/\/\----o    o-------------------------------------
                            |

                          _|__
                          ___  .01 uF
                             |

GND

Check_Switch

 bcf PORTB,0 ; set input to switch 0
 nop
 nop
 nop
 nop
 nop
 nop
 nop
 nop
 movlw b'00000010'
 TRIS PORTB ; change RB1 to input
 nop
 nop
 nop
 nop
 nop
 nop
 nop
 nop
 bcf FLAG,POWER_ON
 btfss PORTB,1
 bsf FLAG,POWER_ON
 movlw b'00000000'
 TRIS PORTB ; put RB1 back to output
 nop
 nop
 nop
 nop
 nop
 nop
 nop
 nop
 return