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@ -396,7 +396,7 @@ |
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<p><strong>RomWBW Hardware</strong> \ |
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Version 3.6 \ |
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Wayne Warthen (<a href="mailto:wwarthen@gmail.com">wwarthen@gmail.com</a>) \ |
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12 Oct 2025</p> |
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13 Oct 2025</p> |
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<h1 id="overview">Overview</h1> |
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<h2 id="supported-platforms">Supported Platforms</h2> |
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<p>This section contains a summary of the system configuration target for |
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@ -2483,7 +2483,8 @@ specifically for ROM-less RomWBW. HBIOS is loaded from disk at boot</p> |
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<p>Eazy80-512 is Eazy80 rev2 pc board configured with 512K RAM to run |
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RomWBW. The design was derived from modifications to Eazy80 Rev1 that |
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supported RomWBW.</p> |
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<p>HBIOS is loaded from disk at boot by ROM monitor</p> |
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<p>HBIOS is loaded from disk at boot by ROM monitor or via a a compressed |
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ROM image.</p> |
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<p>(Not to be confused with EasyZ80)</p> |
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<ul> |
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<li>Creator: Bill Shen</li> |
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@ -2537,6 +2538,31 @@ supported RomWBW.</p> |
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</tr> |
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</tbody> |
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</table> |
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<h4 id="compressed-rom-image-file-rcz80_ez512_std_64krom">Compressed ROM Image File: RCZ80_ez512_std_64k.rom</h4> |
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<p>A 64K ROM image is supported. As there were many areas of \$00 and \$FF |
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bytes in RomWBW, it is possible to compress the 128K RomWBW *.upd file |
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to fit into 64K ROM. The compression routine looks for two or more |
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consecutive bytes of the same value (any values of \$00 to \$FF). If it |
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finds duplicates, it would leave two duplicate bytes followed by a byte |
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count, n-1, (with a max byte count of \$FF) where n is the total number |
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of duplicates.</p> |
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<p>A stand-alone program written in C creates a ready-to-flash binary file |
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for the 64K ROM. The 64K binary file is in the following format. Layout |
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of the 64K ROM:</p> |
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<ul> |
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<li> |
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<p>The first 3 bytes are always \$C3 \$00 \$FF, a jump to the Z80 |
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decompression code located at \$FF00 in the ROM.</p> |
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</li> |
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<li> |
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<p>Locations \$0003 up to, and including, \$FEFF are then available to |
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store the compressed 128K *.upd file.</p> |
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</li> |
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<li> |
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<p>Locations \$FF00 up to \$FFFF, a seperate Z80 decompression routine |
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that executes at startup to decompress the the 64K ROM into RAM.</p> |
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</li> |
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</ul> |
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<h4 id="supported-hardware_22">Supported Hardware</h4> |
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<ul> |
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<li>DSRTC: MODE=STD, IO=192</li> |
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wwarthen
4 months ago