Richard Atkinson wrote: > I haven't looked into this as much as you, Levente, so forgive me if this > is completely unhelpful, but: doesn't the fact that the PS/2 mouse uses a > synchronous protocol clocked by the _host_ machine help? The docs might > specify a fairly high clock rate, but you can (as far as I am aware) > change it, and even send pulses at non-regular intervals; the state > machine in the PS/2 mouse won't know... That would make some sense. I'm not quite sure if this is historically correct, but IIRC, the PS/2 bus was derivated from the ACCESS.bus (no typo there), which was a joint-venture between Big Blue and Philips. The ACCESS.bus was supposed to be an overdressed version of I^2C. I^2C is clearly clocked by the master. A slave can only *stretch* the clock, not narrow it. I've written more_than_one software I2C implementations (on both PC as well as 8051 platforms), using bitbanging. It all works fine, as long as you don't have a multi-master setup (which isn't the case with PS/2 mice) -- Martijn van Buul - Pino@dohd.org - http://www.stack.nl/~martijnb/ Geek code: G-- - Visit OuterSpace: mud.stack.nl 3333 Kees J. Bot: The sum of CPU power and user brain power is a constant. - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail firstname.lastname@example.org.
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