Hi, I am very experienced with microprocessors and digital hardware, but not with steppers. This is my first stepper project, and I am using a DRV8811. I have a bunch of problems, but this first one probably has a lot to do with the others.
When the DRV8811 is powered up, and the motor is not moving, just holding position, there is an annoying hiss. Here is a scope shot of the chopping. The period is 116us, so the frequency is 8.6kHz, which is probably the noise. Given that the charge time (while current is on) is 71us, I don't see how I can get the frequency of the sound up above audible range. The power supply voltage is 24v and can't be changed for the product, and the motor is pretty much fixed also. It's being used with an MSP430.
Any suggestions appreciated.
Lloyd
