Date: 2006-06-06 13:10:59
Hallo allemaal, I had another look at the predecessor of 1541LPT, PC-Flop, and I can announce some success! Having a fresh look at the whole again, I found out I made some mistakes in the past. So it seems I can continue this project as well. What is interesting as well, I piggybacked some IC's on top of the 2nd 6522 that enable me to read a complete track. The next step is to replace the 6522 with this circuit as a stand alone one that should enable me to read the complete floppy through the LPT port. The circuit itself is quite simple: one 74HCT574, one 74LS74 and one 74LS04. The idea is simple as well: the 574 latches the data presented to Port A the moment 'Byte Ready' is active (L). As the 574 needs a rising edge, the 04 inverts this signal. The 74 latches the 'Byte Ready' signal as this one is only active for 1 uSec. One of the outputs of the LPT ports resets the 74 after reading the data. (Hmmmm, it seems I can simplify the circuit to just 2 IC's :) And IMHO, by adding a 541, it should be even possible to use this circuit to write to disks. Unfortunately it requires about 7 outputs to control the various signals, more then available on one LPT port. But I already prooved that that isn't a problem when a COM port is present :) It also looks as if my GCR encoding/decoding routines don't work right: if I encode 4 bytes and decode the result again, the resulting 4 bytes are not always the same as the beginning. Anyone willing to share his sources so I can see where I am going wrong? Many thanks in advance! For anyone with more phantasy then me, I don't like the name PC-Flop. Anyone has an idea for a better name? -- ___ / __|__ / / |_/ Groetjes, Ruud \ \__|_\ \___| URL: Ruud.C64.org =====DISCLAIMER================================================================= De informatie in dit e-mailbericht is vertrouwelijk en uitsluitend bestemd voor de geadresseerde. Wanneer u dit bericht per abuis ontvangt, verzoeken wij u contact op te nemen met de afzender per kerende e-mail. Verder verzoeken wij u in dat geval dit e-mailbericht te vernietigen en de inhoud ervan aan niemand openbaar te maken. Wij aanvaarden geen aansprakelijkheid voor onjuiste, onvolledige dan wel ontijdige overbrenging van de inhoud van een verzonden e-mailbericht, noch voor daarbij overgebrachte virussen. The information contained in this e-mail is confidential and may be privileged. It may be read, copied and used only by the intended recipient. If you have received it in error, please contact the sender immediately by return e-mail; please delete in this case the e-mail and do not disclose its contents to any person. We don't accept liability for any errors, omissions, delays of receipt or viruses in the contents of this message which arise as a result of e-mail transmission. Message was sent through the cbm-hackers mailing list
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