MC33926 - DualMC33926MotorShield.cpp - 100% duty cycle?


I noticed that the max duty cycle for the MC33926 was around 2/3 or something
yet I see that OCR1A and OCR1B are set to 255 at max speed

how can I fix this ?
I need full power for my motors



It sounds like you are using our Arduino library for the Pololu Dual MC33926 Motor Driver Shield. If that is correct, then one immediate issues is that the setM1Speed(), setM2Speed(), and setSpeed() functions from that library expect the speed value to be between -400 and 400, as documented in the README. So, 255 is not max speed; 400 or -400 is.

If that does not explain the issue, can you post what power supply, microcontroller, and motors you are using with your driver along with post some pictures of your setup that show both sides of the driver as well as all of your wired connections? How did you determine that the maximum duty cycle is only 2/3, and can you post the program you are using with the driver?

- Patrick

yeah but why it it not maxing out pwm? when providing 400?
I tried feeding 255 to OCR1A and B but I believe another register must be modified
hence the question

Can you confirm whether you are using the library I linked to and answer the other questions in my previous post? Can you also post a copy of the program you are running?

- Patrick