Hallo allemaal, Solved one problem, bumped into another one. When you insert a 16-bit card it tells the PC by negating MEMCS16. It does this by decoding A17..A23. This is a 128 KB range. So adressing the $Cxxxx range = CGA and MDA, this line is activated AFAIK. So this als must happen if a MDA card is inserted. Now see next table: SBHE A0 Transfer 0 0 word 0 1 byte D8..15 1 0 byte D0..7 1 1 not valid for 16 bit card I could imagine that, when writing a byte to an odd address, you output it on both the lower and upper part of the databus, you could write data to the MDA card. But what about reading ??? FYI: SBHE is activated through a buffer by the processor. Any comment, even vague thoughts or ideas are welcome. Thanks. Groetjes, Ruud http://Ruud.C64.org/ - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail firstname.lastname@example.org.
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