ZHCSR80A June 2009 – January 2023 AMC6821-Q1
PRODUCTION DATA
When the bits [FDRC1:FDRC0] = [00], the fan works in the software DCY control mode. The host writes the desired duty cycle value corresponding to the required RPM into the DCY register. The duty cycle changes to the new value immediately after the writing. In this mode, if the TACH measurement is enabled (bit 2 of 0x01 = 1) and the TACH-MODE bit (bit 1 of 0x01) is cleared ('0'), the duty cycle from the PWM-OUT pin is forced to 0% when the value in the DCY register is less than 7%. However, if the TACH measurement is disabled (bit 2 of 0x01 is cleared) or the TACH mode is set ('1'), the DCY register always keeps the programmed value written by the host and is not forced to '0' even when the programmed value is less than 7%.