Saturday, 9 May 2015

VIC-bankswitching & user-fonts

Today after the hardware is nearly finished I worked at the VIC-emulation.
I added the VIC-bankswitching (VA14, VA15) with 2 inputs in the Xmega. My xmega-VIC can use the RAM under ROM for screen-memory or userfonts - like in the real C64.
Userfonts are now possible:

The xmega detects the characterset-page-switching and loads it completely from the RAM in the xmega-RAM.
After that before every screen row the xmega loads 32 bytes of the actual font - so that about 10 times per second the complete userfont will be new loaded, to get possible changes of the font.
The whole xmage-RAM-downloading of the screen, the colormemory, the register and the userfont steeles the 65c02 only 35 milliseconds of a second !!!

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