Accuracy is pretty good, see committed comments :-)
Code used for testing, in main():
uint32_t i;
SET_OUTPUT(PIO0_1);
while (1) {
// 10 seconds for each frequency, so we
// can measure all three with one upload.
for (i = 10000; i > 0; i--) {
WRITE(PIO0_1, 1);
delay_us(1000);
WRITE(PIO0_1, 0);
delay_us(1000);
}
for (i = 1000; i > 0; i--) {
WRITE(PIO0_1, 1);
delay_us(10000);
WRITE(PIO0_1, 0);
delay_us(10000);
}
for (i = 200; i > 0; i--) {
WRITE(PIO0_1, 1);
delay_us(65000);
WRITE(PIO0_1, 0);
delay_us(65000);
}
}
(Hopefully) no functional change.
Also remove these wd_reset()s in delay_us() to match the behaviour
promised in delay.h. Not that this matters much, watchdog is
disabled by default.