TC or GCLK for external crystal?

Development Boards
1

Hi Folks,

I’m looking at the schematic for the SAMD51 Thing Plus, and I see that the external oscillator is connected to TC / TCC pins (pins 01 & 02) instead of GCLK pins (pins 31 & 32) on the SAMD51J20A chip. Any thoughts as to why SparkFun went the TC route instead of the GCLK route? I’m (slowly) teaching myself about dev board design, and this struck me as odd.

Thanks!

2

I could be wrong, but I think we rely on the SAMD51’s internal oscillator and the crystal we do include is timekeeping for programming a real time clock on the processor.