I have searched the whole datasheet, but couldn't find where are the OSC1 and OSC2 pins are. I've found the CLKOUT (which is CMOS output) on RA4 and CLKIN (which is TTL input) on RA5. But I need the XTAL input/output pins.
I tried connecting my 4 MHz crystal to these CLKOUT & CLKIN with two 22 pF capacitors connected to GND, but it's not working.
I need to use UART on this microcontroller, that's why I need external crystal oscillators.