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85 lines
3.4 KiB
HTML
85 lines
3.4 KiB
HTML
<HTML>
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<HEAD>
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<TITLE>X-LOAD 1.1</TITLE>
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</HEAD>
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<BODY BACKGROUND="6502proc.gif">
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<CENTER>
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<H1>X-LOAD version 1.1</H1>
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<HR>
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</CENTER>
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<H2>INTRODUCTION</H2>
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This tool may be used to load an Atari executable file, stored on the PC,
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into a real Atari computer, via the SIO2PC interface.
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Only data input and data output lines are used, so X-LOAD should work
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with all types of the interface.<P>
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It is experimental version. I'm not sure if it will work
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with every hardware. I've noticed it is not stable and sometimes
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transmission can hang or distortions in loaded data may appear.
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The reason is that there is no error-checking, while transmission is
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fast (57.6 kbits/sec).<P>
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<H3>CHANGES</H3>
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<H4>Version 1.1</H4>
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<UL>
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<LI> files with no explicit run address are started from the beginning
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of the first block
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</UL>
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<H4>Version 1.0</H4>
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<UL>
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<LI> first release
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</UL>
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<HR>
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<H2>USAGE</H2>
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You should pass as the parameters the executable file name and optionally
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the options:<P>
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<DL>
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<DT><TT>/1</TT> - <TT>/4</TT>
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<DD>Serial port number. Default is 2.<P>
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<DT><TT>/p</TT>
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<DD>Force using 'professional loader', which allows you to load code/data
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into the RAM under ROM ($c000-$ffff) and starts the program with disabled
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ROM and interrupts. By default, standard loader is used, which can load
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any Atari executable not demanding DOS or any special loader.<P>
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</DL>
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After you run X-LOAD, you only have to boot your Atari and the program
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will be loaded and run.<P>
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While loading, PC prints memory locations, which the program loads into.<P>
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After the program is loaded and run, X-LOAD terminates. You may exit it
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earlier at any time by pressing the ESC key.<P>
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<HR>
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<H2>DETAILS</H2>
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First, X-LOAD sends a byte to Atari and then waits until the Atari is booted.
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The byte can be used to detect from Atari, that PC is ready for transmission.
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When you are testing your program, you may code periodic checking
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if a byte was received, and performing cold reset in that case.
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So you don't need to touch your Atari to run your program on it.<P>
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While booting, X-LOAD accepts two commands for disk drive 1:<P>
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<UL>
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<LI> <TT>'S'</TT> - read status. Used by the Atari OS to check presence
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of a disk drive.
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<LI> <TT>'R'</TT> - read sector (only first). Used to transfer the loader.
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</UL>
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After the Atari receives and runs the loader, the transmission runs at 57600
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bits/sec.<P>
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The transmission protocol is very simple: Atari sends a byte to inform that
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it is ready for receiving data. Then PC sends a 3-byte header and a block
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of data. First two bytes of the header are the high and the low byte of the
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address of the last byte in the block minus $ff. Third byte equals low byte
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of ($100-block_length). Then come block data, which are loaded directly
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into their memory locations.
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For more details, view source files of the loaders:
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<UL>
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<LI>Standard: <A HREF="xloadstd.asx">XLOADSTD.ASX</A>
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<LI>Professional: <A HREF="xloadpro.asx">XLOADPRO.ASX</A>
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</UL>
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You may have noticed that X-LOAD is somehow similar to X-BOOT, which also
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has two loaders. The main difference is that X-BOOT loaders use system
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routines to get sectors at regular speed of 19200 bits/sec.
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They use sector buffer and require some low memory locations not to be altered
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because of Atari operating system. In this respect X-LOAD loaders are better,
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because they allow loading into whole memory except for the loader code.
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<P><HR><P><A HREF="index.htm">Back</A>
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</BODY>
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</HTML> |