On 2020-02-08 14:22, Michiel Boland wrote: > On 2/8/20 12:25 PM, silverdr_at_wfmh.org.pl wrote: >> Under the lower (and upper) border, the VICs data sequencer is stuck >> at the last byte of the selected video ram bank ($3fff for default >> bank 0). That's where the bitmap data comes from. Does anyone >> know/remember where its colour information comes from? Or is it >> always $x0 as "unconnected"? >> > > The color of a pixel is determined by either the value of some color > register (any of $d020-$d02e) or some selection from the 40x12bit > cache. There are 40 word lines connected to the cache that get > activated in sequence during normal display (see my previous ramblings > about this in the archive). > > Outside of the display (in normal operation, between lines 251 and 51) > the word lines are not activated, so the bit in the chip that reads > the color bits from the cache reads all zeroes, i.e. black color. > > This is also the reason that the display becomes entirely black > outside of the border if you turn on bit map mode (since then both > foreground and background color are determined by the 40x12 cache.) > > Cheers > Michiel > This was actually something I was wondering about some time ago. I know the border turns black with bitmap mode + hires, had to deal with that from time to time, but I could never fully explain why. So thanks for that :)Received on 2020-05-30 00:54:30
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