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counting a LOT of quadrature inputs with 56F807

Started by kiha...@gmail.com February 27, 2006
Hi, I'm trying to build a board with 56F807, which can count 7 different
quadrature inputs if I use quad timers and quad decoders. But I would like to
have an option to count from more than 7 quadrature inputs.

So I programmed a 4-state (00, 01, 11, 10) finite state-machine, which takes
inputs from one of the GPIO pins, and polled at a set frequency. For example, if
the previous input was 00 and the new input is 01, it would upcount; and if the
new input is 10, it would downcount. This sounds like it should work, but
apparently it doesn't match the results from the hardware decoders. Can someone
suggest me suggestion or better solutions?

If anyone knows of any multi-axis quad counter ICs that can interface serially
(SCI, SPI, or CAN), I would like to know about it.

Thank you,
Ko Ihara

I suggest to add a F8013 for additional 2 quadrture
decoders. Communication between F8013 and 807 can be
SPI.
 Charlie
--- kihara@kiha... wrote:

> Hi, I'm trying to build a board with 56F807, which
> can count 7 different quadrature inputs if I use
> quad timers and quad decoders. But I would like to
> have an option to count from more than 7 quadrature
> inputs.
> 
> So I programmed a 4-state (00, 01, 11, 10) finite
> state-machine, which takes inputs from one of the
> GPIO pins, and polled at a set frequency. For
> example, if the previous input was 00 and the new
> input is 01, it would upcount; and if the new input
> is 10, it would downcount. This sounds like it
> should work, but apparently it doesn't match the
> results from the hardware decoders. Can someone
> suggest me suggestion or better solutions?
> 
> If anyone knows of any multi-axis quad counter ICs
> that can interface serially (SCI, SPI, or CAN), I
> would like to know about it.
> 
> Thank you,
> Ko Ihara
>