On Mon, 21 May 2001, [ISO-8859-1] Marko Mäkelä wrote: > On Friday, I acquired a 8032 and a 8023P printer. When I looked at the > expansion connector (it is hidden behind the case of my 8032-SK), I got an > idea: Would it be possible to build a cartridge that can be fitted both to > a 8032 and (with a little sawing) to a VIC-20? The circuit board would > look like this (use fixed-width font to view it) > My question for PET experts is: Are there free I/O block selection signals > on the expansion port? And regarding the 6545 CRTC: are the registers R18 > through R31 unassigned? Block 8, A, and B are available. Screen memory only takes 2K so $8800-8FFF should be available The PET only uses registers 0-9 and 12-17. Printing chr$(14) or chr$(142) to change character sets causes the system to reload the CRTC registers, so this might interfere with what you are doing, but probably not register 18 and up. There were some programs that did graphics by manipulating the CRTC. Since there were several versions of CRTC in use, these programs did not always work. - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail cbm-hackers-request@dot.tml.hut.fi.
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