rbaltiss@worldaccess.nl wrote: > Question: is it possible to send me the SCH of your (final) version of the IEEE > interface for the LPT-port? Uhm. Sorry, I have not (yet) finished this. I have all parts and I have the schematics but not yet resoldered the board to the new Sch. So the new Sch would not be tested, but if you still like I can send them to you. > > After all by switching the _charrom_ to graphics mode.... > How this is done on the PET? I found out by poking 59468,12. but that > (certainly) is not the friendly way to do it. As far as I know (probably PETdoc or pet-FAQ prove me wrong) this is the only way. Probably there is a PRINT CHR$(??) as in the C64. > I disagree. 128 ASCII characters PLUS 128 graphic-characters makes 256. Double > it for inverting makes 512. 512 * 8 = 4096 = 6332. > So only ASCII + invert = 6316. Do don't need to double it for inverting! The 7th bit of the byte read from memory does not go to the charrom but directly to an exclusive-or with the shiftregister output that generates the pixel stream! So you have only 7 address bits for the charset, plus 1 bit for text/graphic and 1 bit for us/nationalized, plus 3 bit for the rasterline number, gives 12 bits that make 4kByte to fit in a 6332 _with_ the nationalized charset. > > But setting it on the nationalized one could probably switch between > > us and nationalized charsets (as the DIN key does in german C128 machines). > > I do have a German C128 as well. (They were much much cheaper then here in the > Netherlands) And the CHARROM is a 2764 = 8KB in my case! The C64/C128 doesn't have the hardware inverter, so you have to double the size of the charrom. Makes 4k for 256 chars * 2 (text/graphics) * 8 (bytes/ char) is 4k for the C64, and *2 for the nationalized charset in the C128 makes it 8k. hope it helps Andre -- Email address may be invalid. Use "fachat AT physik DOT tu-chemnitz DOT de" ------Fight SPAM - join CAUCE http://www.cauce.org------Thanks, spammers... Andre Fachat, Institute of physics, Technische Universität Chemnitz, FRG http://www.tu-chemnitz.de/~fachat
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