Re: PS/2 mouse as 1351?

From: Marko Mäkelä (
Date: 2003-09-17 08:00:31

On Wed, Sep 17, 2003 at 01:27:11AM +0200, Groepaz wrote:
> On Tuesday 16 September 2003 23:51, Maciej Witkowiak wrote:
> > Are there any other options?
> maybe use 2 inverters in series or sth like that to improve signal quality?

There's no need to invert the signal twice.  One inverter is enough, since
the active edge of the AVR interrupt inputs can be configured.

The inverter could perhaps be implemented with an NPN transistor.  You could
maybe even make use of the internal pull-up resistors of the AVR I/O pins.


PS: What is the smallest AVR that has an SPI bus?  For instance, the 2313,
which would otherwise be up to the task, has it only for programming purposes.
I believe, however, that you could use bit-banging on the 2313 like Levente
did on the PIC.  On the PS/2 interface you even have the advantage over
RS-232 that the clock is driven by the "computer", isn't it?

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