pico-tracker/firmware/Peripherals.md

SAM D20 Peripherals usage

Type	Peripheral	Function	Notes
GLCK
	gclk0	main clock, internal osc8m	4 MHz
	gclk1	tcxo clock, fed from xosc OR osc8m
	gclk7	aprs clock, fed from gclk1, div 6 / 11

|TC|| ||tc0|telemetry tick timer. 32-bit ||tc1|^^^^^ ||tc2|counts cycles of tcxo. 32-bit ||tc3|^^^^^ ||tc4|osc8m event source ||tc5|telemetry pwm 16-bit

|EXTINT| ||extint[5]|gps timepulse

|event channels| ||0|event source for timer 2 xosc measurement ||1|tc4 retrigger

|SERCOM|| ||sercom0|spi flash ||sercom1|ublox gps ||sercom2| ||sercom3|radio|currently bitbanged as required pin layout broken in sercom

SAM D20 Interrupts usage

Name	Function	Priority H(0-3)L	Notes
TC0_IRQn	telemetry tick timer	0
TC2_IRQn	xosc measurement done	2
[GPS_SERCOM]_IRQn	gps usart rx	0
EIC_IRQn	timer	1