On Thu, 27 Jun 2002, Robert Rolf wrote:

>Given the constraints (2 inputs), a quad op-amp and a 74hc00 or equivalent.
>Op-amps turn the low level bipolar sine/cos waves into sufficient amplitude
>to drive the 74HC00's which are configured as set/reset latchs.
>You bias the op-amps so that the over zero part of the signal sets the latch,
>and the under zero part clears it.

I think that you can use a latchless version connected with interrupt on
change. I think that using even two bipolar transistors w/o bias will be
enough. The stepper produces a pulse of several volts even when moved
slowly. I think that there is no need to look at all four states because
the stepper should produce at least one positive pulse per detent. This
needs to be tried though.

Peter

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