Hello,

I am trying to figure out why the kit comes with an 14.7MHz oscillator. The oscillator is connected between pins 6 and 7 in port B (XSTAL1, XSTAL2). Why is the kit using this oscillator and not an internal clock?

This post explains it:

link

Here's a snippet:

We chose 14.74756 MHz because we wanted to enable high-data-rate serial communications to and from the PC. Commonly-available standard UART rates go up to 115200 baud (i.e. the clock rate on the serial port line is 115.2 kHz). So 14.7456MHz may seem like a strange number, but it was chosen because it evenly divides to 115200. (14745600 / 128 = 115200.)