I was updating a motor-driver source from some years ago. I use the timers of a EFM32GG280 processor. To have more precision for PWM, I started using the timer 2x-count mode. So I had to look up some info and downloaded a newer (revision 1.20) of the EFM32GG-RM.pdf document.
I wondered about some equations for PWM in 2x-count mode:
(20.7) f PWM 2xmode = 2 x f HFPERCLK / floor(TOP/2)+1
I think this should be "f HFPERCLK / floor(TOP/2)+1", because the factor 2 is already in the "TOP/2" part.
(20.8) DS 2xmode = CCVx/TOP
I think the PWM up is only 100% when CCVx is equal to TOP+2.
(20.5) DS up = CCVx/TOP
Same as (20.8), but TOP should be added with 1.
Also in February 24 20154 we discussed "Problem with timer in quadrature encoder mode with UF and OF interrupt". It was not working and I tried it with a newer EFM32GG280 version. It is still not working and it is also not added to the documentation. Should it work with a certain EFM32GG280 revision?
I hope my feedback is useful.
kind regards, Erik
I am waiting for some confirmation regarding your first question, but as far as the quadrature encoder problem is concerned, we will be adding it to our errata and this has not been fixed currently. More recent MCUs such as EFM32PG1, EFM32PG12, EFM32JG1, JG12 etc do not have an issue with UF/OF flags in quadrature mode.