>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. People have use the tape port on the C64/C128 to interact with PC keyboards, these also use O/C logic. The implementations are essentially "listener only", which might work, but a drive needs to be "talker" and "listener". >From memory the cassette port has no O/C circuit, but one line has a pull up resistor (the sense), another a transistor driver circuit(motor), and the read/write lines are straight through from the 6526/CPU, respectively. I imagine a professional cassette port adaptor would probably include O/C driver chip. - Nick PLEASE TAKE NOTE: The contents of this email (including any attachments) may be privileged and confidential. Any unauthorised use of the contents is expressly prohibited. If you have received this email in error, please advise us immediately (you can contact us by telephone on +61 8 9441 2311 by reverse charge) and then permanently delete this email together with any attachments. We appreciate your co-operation. Whilst Orbital endeavours to take reasonable care to ensure that this email and any attachments are free from viruses or other defects, Orbital does not represent or warrant that such is explicitly the case (C) 2000: Orbital Engine Company (Australia) PTY LTD and its affiliates - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail firstname.lastname@example.org.
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