On Sun, 17 Sep 2000, Hársfalvi Levente wrote: > As speaking of the PS/2 mouse plan, after reading the specs (thanks to > Richard) I see it'll reveal much more problems in the code than the > RS-232 (async) communication ever had :-(. The problem is, the bitrate > is quite high. According to the docs, the bit time is about 30-50 > microseconds. I can delay the byte transmit even for several > milliseconds, but unfortunately not during transmitting a byte > (transmitting a particular bit in a byte can't be delayed). During > generating the duty cycle for the POTX/POTY inputs for the SID in 1351 > mode, the microcontroller can be off even for 140-150 cycles (because of > the needed exact timing). (One cycle corresponds to one microsecond @ 4 > Mhz osc clock). 'Of course', the PIC16c84 has no SPI interface or > similar toy, one has to do everything by software. Bit banging rulez > like hell... :-/ 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... Richard -- Richard Atkinson Software Engineer Tenison Technology EDA Ltd http://www.tenisontech.com/ - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail firstname.lastname@example.org.
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