On Tue, 24 Apr 2001 firstname.lastname@example.org wrote: > >what was this person up to? Is such a hack even POSSIBLE in a >710/720? > Can > >Commodore Serial disk drives be driven from the lines in the >>datasette > >port?!?! > > To drive the IEC serial bus Open Collector chips are normally needed so that > there is no conflict between various devices working the bus. If there is no > 7406 (or similar) chip in the circuit, chances are it is a naive attempt at > the modification, and potentially risky. The O/C function allows devices to > pull the signal "low" and to "let go". Without the "let go" function, you > get "pull high" which can lead to a bus contention. Unless a clever programmer sets the outputs to '0' and uses the DDR to toggle the lines ;) THis would give you your pull and let go feature. The only thing you need beyond this is a pull-up resistor on each line. - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail email@example.com.
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