I'm trying to intercept the signals between an old Elan uC and a HT-1622 LCD driver using a PIC18F14K50. There are 3 lines that are connected to the IOs of the uC: CS, WR(write clk) and DATA. At first sight it looks pretty simple, I just soldered 3 cables between the inputs on the HT-1622 and RB4, RB5 and RB6 on the PIC, and then I configured the registers like this:
TRISB = 1; // set all pins on port b as inputs ANSELH = 0; // digital inputs WPUB = 0; // disable the pull-up resistor
The problem arises when the PIC is powered on, the LCD driver stops working as it should, and the signals I get on the PIC inputs aren't valid (they're always 1). Once I disconnect VCC on the PIC, the LCD Driver works again. So it seems I'm missing something, any thoughts?