On 28 April 2010 09:46, Erik Christiansen <[email protected]> wrote:
>> It is also rather out of the scope of the AVR microcontrollers, which >> have a max PWM rate of (Base Clock / 512) > > Err, have you examined the range of AVR microcontrollers, and their > variety of on-chip hardware enhancements? Clearly not. I should have been more specific that I had only looked at the options on the Arduino boards. But more importantly I am completely wrong about them too! I have managed to make the initial error of confusing PWM rate with PWM Clock Timer Rate in the other direction when looking at the capabilities of the Arduino board. I was thinking that the 2kHz sine wave I am using for the Resolver interface meant that that was the max PWM rate, but of course that is the sinusoidal modulation that I am superimposing on the 31kHz PWM, so not only is 10kHz PWM trivial for an Arduino, I am actually already using it at three times that frequency > Just glancing at the AT90PWM3 > datasheet shows that each PSC will clock at 64 Megahertz, with 12 or 16 > bit resolution. ============ > > At first glance, that suggests that on 12 bit resolution, it can't quite > get _down_ to 10 kHz! If it is anything like the Atmega328 used on the Arduino board I have then there is a programmable divider between the system clock and the PWM timer clock, so getting down to 10kHz is straightfoward. The uC used in the Arduino boards have a 1024 max divisor which gives 30Hz PWM and the other versions might have a wider divisor range. -- atp ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
