Re: [Gumstix-users] Re: gumstix-users digest, Vol 1 #638 - 9 msgs

[Dave H. <dhy...@gm...>]

Hi Brendan,

On 7/15/05, Brendan Simon <Bre...@fa...> wrote:
> I download WinAVR and could see no reference to quadrature encoder
> counters in the avr library.
> Where are you looking to get this info.
>=20
> What do you mean by direct access registers?
> Do you mean directly accessable from the outside world or just from the C=
PU?
> I presume you mean the latter, in that there are a number of internal
> registers for general purpose use???

There is no direct hardware support for quadrature encoding in the AVR.

There is 2K os SRAM on the chip that can be used to store all kinds of
things. It's a general purpose CPU.

This web page:
http://www.barello.net/Papers/Motion_Control/index.htm
Scroll down to the section "Appendix A: Quadrature Decoding State
Machine" has some code for doing quadrature decoding.

What frequency does your quadrature decoder need to support?

--=20
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/