Interrupt block with different exit?

[richard]

just a few comments

trying to capture a serial stream with a bit-banged routine triggered from an isr is difficult to make reliable far better to use the eusart module.
to reset rbcif flag you need to make sure the pin involved is in a steady state[ not still receiving data] and do a read of portb immediately before exiting isr
alias your leds to lat regs not ports, dont use high/low
be aware that a pic-chip is not a power supply there is a maximum total pin current
your code seems to call validat over and over an over yet never returns , the stack won't be happy about that