// This assumes PRUSS is clocked at 200 MHz, which is its typical clock frequency.
//
// A more generic version of this code for any frequency and period: https://pastebin.com/rBR4v35a

// Initialization from python (using py-uio):
//    pruss.ecap.pwm.initialize( 200000000 )  # 1 second period

struct Timestamp {
	uint32_t s;
	uint32_t ns;
};

// Returns timestamp in seconds and nanoseconds (with 5ns precision).
// Must be called at least once every second to ensure correct timekeeping.
struct Timestamp timestamp()
{
	static struct Timestamp now = { 0, 0 };
	uint32_t ns = CT_ECAP.TSCTR * 5;
	if( ns < now.ns )  // ecap counter has wrapped
		++now.s;
	now.ns = ns;
	return now;
}