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105 lines
3.7 KiB
HTML
105 lines
3.7 KiB
HTML
<HTML>
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<TITLE>ANTIC Documentation</TITLE>
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<BODY BACKGROUND="atari.gif">
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<H1>ANTIC Documentation</H1>
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by <A HREF="mailto:pfusik@elka.pw.edu.pl">Fox/Taquart</A><P>
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<HR>
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<P>
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<H2>Registers</H2>
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<TABLE BORDER>
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<TR><TD><I> Address </I></TD><TD><I> Read register </I></TD><TD><I> Write register </I></TD></TR>
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<TR><TD ALIGN=center><TT>^40</TT></TD><TD>unused</TD><TD><A HREF="#dmactl">DMACTL</A></TD></TR>
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<TR><TD ALIGN=center><TT>^41</TT></TD><TD>unused</TD><TD><A HREF="#chrctl">CHRCTL</A></TD></TR>
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<TR><TD ALIGN=center><TT>^42</TT></TD><TD>unused</TD><TD><A HREF="#dlptr">DLPTRL</A></TD></TR>
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<TR><TD ALIGN=center><TT>^43</TT></TD><TD>unused</TD><TD><A HREF="#dlptr">DLPTRH</A></TD></TR>
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<TR><TD ALIGN=center><TT>^44</TT></TD><TD>unused</TD><TD><A HREF="#hscrol">HSCROL</A></TD></TR>
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<TR><TD ALIGN=center><TT>^45</TT></TD><TD>unused</TD><TD><A HREF="#vscrol">VSCROL</A></TD></TR>
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<TR><TD ALIGN=center><TT>^46</TT></TD><TD>unused</TD><TD>unused</TD></TR>
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<TR><TD ALIGN=center><TT>^47</TT></TD><TD>unused</TD><TD><A HREF="#pmbase">PMBASE</A></TD></TR>
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<TR><TD ALIGN=center><TT>^48</TT></TD><TD>unused</TD><TD>unused</TD></TR>
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<TR><TD ALIGN=center><TT>^49</TT></TD><TD>unused</TD><TD><A HREF="#chbase">CHBASE</A></TD></TR>
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<TR><TD ALIGN=center><TT>^4A</TT></TD><TD>unused</TD><TD><A HREF="#wsync">WSYNC</A></TD></TR>
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<TR><TD ALIGN=center><TT>^4B</TT></TD><TD><A HREF="#vcount">VCOUNT</A></TD><TD>unused</TD></TR>
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<TR><TD ALIGN=center><TT>^4C</TT></TD><TD><A HREF="#lpenh">LPENH</A></TD><TD>unused</TD></TR>
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<TR><TD ALIGN=center><TT>^4D</TT></TD><TD><A HREF="#lpenv">LPENV</A></TD><TD>unused</TD></TR>
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<TR><TD ALIGN=center><TT>^4E</TT></TD><TD>unused</TD><TD><A HREF="#nmien">NMIEN</A></TD></TR>
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<TR><TD ALIGN=center><TT>^4F</TT></TD><TD><A HREF="#nmist">NMIST</A></TD><TD>unused</TD></TR>
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</TABLE>
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<P>
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<HR>
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<P>
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<H2>Description</H2>
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</CENTER>
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<A NAME="chbase"><U>CHBASE</U>
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- <B>Characters base</B><BR>
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Contains high byte of character set in text modes.<P>
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<A NAME="chrctl"><U>CHRCTL</U>
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- <B>Characters control</B><BR>
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bit 0 - display characters 128-255 as spaces<BR>
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bit 1 - display characters 128-255 as inverse<BR>
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bit 2 - display all characters upside down<P>
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<A NAME="dlptr"><U>DLPTRL</U> <U>DLPTRH</U>
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- <B>Display List pointer</B><P>
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<A NAME="dmactl"><U>DMACTL</U>
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- <B>DMA control</B><BR>
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bits 1,0 - width of screen<BR>
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00 - screen off<BR>
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01 - narrow screen - 256 pixels<BR>
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10 - normal screen - 320 pixels<BR>
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11 - wide screen - 384 pixels<BR>
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bits 3,2 - DMA for Players/Missiles<BR>
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00 - no DMA for P/MG<BR>
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01 - DMA for missiles<BR>
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10 - DMA for players and missiles<BR>
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11 - DMA for players and missiles<BR>
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bit 4 - P/MG resolution<BR>
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0 - 120 lines<BR>
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1 - 240 lines<BR>
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bit 5 - DMA for Display List<BR>
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bits 7-6 - unused<P>
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<A NAME="hscrol"><U>HSCROL</U>
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- <B>Horizontal scroll</B><P>
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<A NAME="lpenh"><U>LPENH</U>
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- <B>Light pen horizontal position</B><P>
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<A NAME="lpenv"><U>LPENV</U>
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- <B>Light pen vertical position</B><P>
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<A NAME="nmien"><U>NMIEN</U>
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- <B>NMI enable</B><BR>
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bits 5-0 - unused<BR>
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bit 6 - enable VBLKI<BR>
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bit 7 - enable DLI<P>
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<A NAME="nmist"><U>NMIST</U>
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- <B>NMI status</B><BR>
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bits 5-0 - unused<BR>
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bit 6 - VBLKI occured<BR>
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bit 7 - DLI occured<P>
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<A NAME="pmbase"><U>PMBASE</U>
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- <B>Player/missile base</B><BR>
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High byte of P/MG data<P>
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<A NAME="vcount"><U>VCOUNT</U>
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- <B>Vertical count</B><BR>
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Contains number of scanline divided by 2.<P>
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<A NAME="vscrol"><U>VSCROL</U>
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- <B>Vertial scroll</B><P>
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<A NAME="wsync"><U>WSYNC</U>
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- <B>Wait for synchronization</B><BR>
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Any value written to this register stops CPU until right border of normal screen is reached.<P>
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