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diff --git a/instructions.txt b/instructions.txt new file mode 100644 index 0000000..730f513 --- /dev/null +++ b/instructions.txt @@ -0,0 +1,266 @@ + DS81 + ---------==============================--------- + + Copyright 2006 Ian Cowburn + ianc@noddybox.co.uk + + +1. LICENSE +---------- + + The code to DS81 is released under the GNU General Public License. See + the text file COPYING for details. + + Other included software is provided in good faith, is not released under + the GNU General Public License, and is copyright their respective authors. + If any of these authors disagree with the distribution of their work then + contact me and it will be gladly removed. + + ZX81 BASIC ROM (c) 1981 Nine Tiles Networks LTD + 3D Monster Maze (c) 1983 Malcom E. Evans + Mazogs, City Patrol and Sabotage (c) 1981, 1982 Don Priestley + + +2. ZX81 +------- + + The ZX81 was an 8-bit computer released by Sinclair Research in 1981, using + the Z80 CPU. + + It was a monochrome machine with no sound (be quiet those at the back of + the room who used to be able to do sound by doing odd things with the video + signal) and a text mode that could be used to plot graphics at a resolution + of 64 by 44 (hmmm, smaller than most icons nowadays). + + It came with 1K of RAM, though most people opted for a massive 16K RAM pack. + + +2. DS81 +------- + + DS81 is an emulation of the 16K ZX81 and is is supplied in two main forms, + as a native Nintendo DS executable and a version with a Gameboy Advance + wrapper (in case your Ninentdo DS homebrew device only supports running + GBA executables). + + In addition to this two different versions are supplied, one which + initialises the FAT library and one which doesn't. They are identical save + for this, and separate ones are supplied in case the FAT library + initialisation causes problem on your homebrew device: + + ds81.nds - Nintendo DS version + ds81.ds.gba - As above with a GBA wrapper. + + ds81-nofat.nds - Nintendo DS version; no FAT library initialisation. + ds81-nofat.ds.gba - As above with a GBA wrapper. + + I'm probably being overly paranoid there, but better safe than sorry. + + In any of the following sections where files are mentioned it obviously + doesn't apply to the 'nofat' versions. + + +3. Using DS81 +------------- + + When run DS81 displays a splash screen with copyright information and + whether the FAT library has been able to find a supported device for the + loading of external tapes. + + Once the A button has been pressed the ZX81 resets and displays itself + on the top screen, and a soft keyboard is displayed on the bottom, touch + sensitive, DS screen. + + If you've never used a ZX81 before then you may wish to find out how the + keyboard works -- it uses a keyword entry system, rather than the straight + typing if commands. So, for instance, the key P is pressed to enter PRINT + when the cursor is in keyword mode (the cursor in an inverted K). + + Trust me; you were glad of it when using the original ZX81's hard plastic + membrane keyboard. + + When using the soft keyboard by default the shift key is 'sticky' and once + used will stay held down until pressed again. + + The World of Spectrum has the original ZX81 manuals, either as a PDF + or in HTML form: + + http://www.worldofspectrum.org/ + + At the bottom of the keyboard is an area where you can click to bring up a + menu. Either use the stylus, or the joypad and button A to select an + option from the following choices: + + RESET ZX81 + This resets the emulated ZX81. + + SELECT TAPE + Selects the built-in tape to use (DS81 has a number of ZX81 tapes + built into it). The next section has extra information on the + loading of games. + + CONFIGURE + Lets you configure settings (see last section for settings). + + If you press SELECT to exit the configuration screen then the + configuration is saved into the file /DS81.CFG which is read on + start-up. + + MAP JOYPAD TO KEYS + Allows you to redefine the DS's joypad and buttons to ZX81 keys. + Follow the on-screen instructions. + + MACHINE CODE MONITOR + Provides access to a basic machine code/memory monitor. This lets + you watch the ZX81 execute op-codes, or single-step over them. + + Unless you're actually interested in such things you'll never need + to go near this option -- it's there to track down emulation bugs + as much as anything. + + See the second to last section for more details. + + CANCEL + Cancels the menu. + + + +4. Using the internal tapes on DS81 +----------------------------------- + + Games on the ZX81 were supplied on cassette. DS81 includes a few tape + files that are selectable from the menu. Follow the on-screen instructions + to select the game. A quick description and the controls to use are + displayed on the top screen. + + Once you've selected a tape you can load it in the emulator by using the + command LOAD "". If you're really stuck with the ZX81 keyboard: + + 1. Select your tape. + 2. Reset the ZX81 from the menu. + 3. When the inverse K cursor is displayed press the J key to generate + the keyword LOAD. + 4. Press the SHIFT key. + 5. Press the P key twice to enter the double quotes (DON'T use the + double quotes got by pressing SHIFT+Q. These are not the same!) + 6. Release the SHIFT key and press the NEW LINE key. + 7. The tape will load and run. + + +5. Using external tapes on DS81 +------------------------------- + + If you are using the version of DS81 that allows the use of FAT devices, + and you device is supported, they you can load any old tape. + + FAT support is via the new DLDI interface, so you may need to dynamically + link in the appropriate FAT driver. Details are available here: + + http://chishm.drunkencoders.com/DLDI/index.html + + Note that the default driver linked in is the Datel Max Media Dock + (Compact Flash) -- solely as that's what I have. + + Simply place the .P file (ZX81 games are usually distributed as .P files + that are simply an image of the memory that would have been dumped to tape) + and either put it in the root directory of the FAT device or in a directory + called ZX81SNAP. + + Alternatively if you can't remember the names of files, loading "*" will + give you with a file selector to select the tape file with. + + It can't be at all guaranteed that all original ZX81 games will work as + expected. After all, DS81 isn't really a ZX81. + + +6. High Resolution Support +-------------------------- + + There is now some support for high-resolution ZX81 games. Currently + it doesn't run quite full speed, and it won't work if the routines are + too clever - unfortunately, like Manic Miner where it switches between + high and low-resolution in the same frame. + + I know the Software Farms games seem to work, though "Forty Niner" + sometimes goes mad (just incrementing the score) though that's probably + a general emulation bug. Of course unless it did that anyway -- I've never + played it before. + + Steven McDonald's games seem to cause no-problem so far. + + If a game doesn't look right it may also be worth enabling the 'RAM AT 8192' + option. + + If you know of a game that seems to cause it real trouble, please let me + know -- the high-resolution support is still a bit of a hack whereby the + 'emulator searches memory for the display file on detecting that the 'I' + register has changed. + + +7. Machine Code Monitor +----------------------- + + On starting the machine code monitor the keyboard will go dim and get + overlaid with a text display showing you the Z80 instructions about to be + executed along with the current states of the registers in the Z80. + + The keyboard is dim, but still on display as the montitor does let you + use the keyboard. Note that all keys are sticky (like the shift key in its + default state) and that joypad mappings are ignored. + + With the monitor on display the following joypad keys can be used: + + START - Toggles between running continuously and single-step mode. + + A - If in single-step mode then executes the next instruction. + + X - Display a help page. + + SELECT - Toggles between the current disassembly/CPU state display, + a disassembly or a hex-dump of memory. + + L/R - The shoulder buttons change the address being displayed on + the memory dump. Hold the Y key at the same time to make + it jump in bigger steps. + + B - Cycles the value used for the memory dump or assembly views; + either the address as set with the shoulder buttons, or one + of the registers: HL, IX, SP, IY, BC, DE or PC. + + Press the config bar at the bottom of the soft keyboard to exit the + machine code monitor and return to normal running. + + +8. Configuration Options +------------------------ + + STICKY SHIFT + + This option allows you to decide whether the shift key on the soft + keyboard is sticky (toggles when you press it) or acts like the other + keys. You should never need to make it non-sticky unless a game needs + it. + + AVERAGE TOUCHSCREEN + + This option can be enabled if your touch-screen seems to suffer from + jumps (mine seems to once in a while) and causes the soft keyboard to + only register touchscreen presses if they are within 5 pixels of each + other over two frames. Your mileage my vary, but for me it stops the + menu randomly appearing. + + This means that response can be reduced by a frame, but it shouldn't + cause problems. + + RAM AT 8192 + + One hardware fix that could be made to the ZX81 was to replace the + mirror of the ROM that started at 8192 with RAM. This allowed + true high resolution graphics. + + Not that I've found any that work yet :-) + +------------------------------------------------------------------------------- +$Id$ + + vim:expandtab:spell |