rackley said:
It perplexes me that the relay output works perfectly, which means the PIC is indeed running OK,
Yes. PIC is definitely working. Just make sure the PIC port pins for LCD do not float during operation. I do remember certain PIC port pins(RA4??) do float even in output mode.
rackley said:
but the LCD output gets all garbled. And it's not an LCD problem because I replaced the LCD. :shock:
So it is not hardware problem as you have replaced both PIC and LCD. But have you eliminated software communication problems, especially when you are using an exceptionally long LCD connecting cable?
Most connecting cables for LCD are short, within a few inches. A 2.5 feet cable might work, but would require the programmer to reduce the clock speed of the data transfer between the two.
To prove/disprove this just fit a 1MHz crystal/resonator and test the circuit. If it works then your problem is comunication timing.