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  • V6Z80P Update Roundup

    Posted on June 11th, 2009 Phil

    Work on the Z80 Project continues, here’s a list of recent updates:

    OSCA – FPGA architecture:

    • Interlace timing mode, increases the vertical resolution 2x on PAL and NTSC TVs.  Would be easier to use if the bitplane pointers had line modulos, something I may look into later.
    • Sound system interrupts. There are now flags which become set when each channel loops (re-reads its location and length pointers). These flags are OR’d into a new interrupt source. This allows long samples to be played seamlessly as the buffer data and pointers can be set up ahead and switched when the previous buffer has been played.
    • Double buffered palette – saves the need to write to the palette registers off screen to avoid glitches.
    • New Sprite modes – X mirror image, Matte mode (forces all non-zero pixels to a single colour) and high palette  (sets bit 7 of pixels indexes, providing a simple means of switching video priority per sprite)

    FLOS – Operating system

    • OS can now be assembled to use FAT16 instead of my own filesystem, alas no room for both.
    • Rewrite of the text plotting code, now uses to the blitter – allows colour in the fonts (15 foreground and background colours)
    • Added new Kernal (sic!)  commands for directory listing, character plotting,  low level sector access..

    Meanwhile, other V6Z80p owners have been making some nice programs.. Valen has provided a C framework for using SDCC with the V6Z80p and Daniel has made a PT3 tracker player.

  • Eyup, it’s all gone “WordPress”

    Posted on June 3rd, 2009 Phil

    I’ve given into peer pressure and converted Retroleum to WordPress.  Most of the old site has been changed to suit, but some of the older articles remain to be done (beware of broken links too).  The more “bloggy” format and ease of updating offered by WordPress may mean this front page gets updated more often..  and then again it may not :) Updates are more visible anyway..

    Still one V6Z80P for sale BTW…