Here is what the datasheet says about this:
"If judge bit is 1, it means frequency mode. If judge bit is 0,
it means duty cycle mode."
But this is plain wrong. Reality proves this is the other way around.
Depending on the chip, the limit value for the buzzer is between 25 and 35 Ω,
so this code set the limit for continuity to 25 Ω to be on the safe side.
Aurelien Jacobs
Martin Ling
Uwe Hermann