My basic question is whether it is possible to replace the ceramic resonator that determines the clock frequency of an Arduino Mega 2560 with a crystal of a different frequency? Also, if I did this, would the bootloader, the USB serial link etc still work, and if not, is there anything that I could do about this?
More specifically, I am trying to use USART 1 of an Arduino Mega 2560 to communicate with some old hardware that has a UART hard-wired to have a serial baud rate of 187.5kbaud. With the default Arduino clock frequency of 16MHz, none of the available Arduino USART baud rates are close enough to the required 187.5Kbaud. So I am wondering whether it would be possible to replace the 16MHz ceramic resonator on the Arduino board with a 14.7456MHz crystal? At this alternate frequency I could get the desired baud rate. There are two pads either side of the resonator on the Arduino board that look about the right distance apart for a crystal, but I can't tell whether the capacitors near this are wired appropriately for a crystal etc...
Any advice would be appreciated.