PCA9685 servo question: setAlwaysOff sometimes makes the servo jump to zero position about pi4j-v1 HOT 3 CLOSED

I can confirm that simply setting PCA9685A_LED0_OFF_H's bit 4 to high works - the motors are off, and there are no erratic movements. So definitely asynchronously setting the lower bits to zero first is wrong.

from pi4j-v1.

Could it be that the "independent" write commands cause problems? I'm not familiar with i2c, but how does it prevent that the last PWM cycle is "cut off"? or does it always complete one cycle? would using a single void write(byte[] buffer) instead of four individual byte writes help? I see there is an internal locking mechanism, but not sure this has anything to do with ensuring the entire command is atomically received by the chip.

from pi4j-v1.

the other thing I see in setFrequency is that there is some "sleep" mode, e.g.

            oldMode = device.read(PCA9685A_MODE1);
            int newMode = (oldMode & 0x7F) | 0x10; // sleep
            device.write(PCA9685A_MODE1     , (byte) newMode); // go to sleep
            device.write(PCA9685A_PRESCALE  , (byte) prescale);
            device.write(PCA9685A_MODE1     , (byte) oldMode);
            Thread.sleep(1);
            device.write(PCA9685A_MODE1     , (byte) (oldMode | 0x80));

perhaps something like this "sleep" should be used instead of setAlwaysOff?

from pi4j-v1.