TTTTTTTTTT XX XX TTTTTTTTTT TT XX XX TT TT XX TT TT XX TT TT XX XX TT TT XX XX TT Version 2.0 01-May-87 Version 2.0a 11-Dec-88 By: Harrie F.A. de Leeuw Contents ..................................... 1. Preface ................................... 2. Hardware .................................. 3. Operating the TXT program ................. 3.1. What is on the desk .................. 3.1.1. The selection box ............. 3.1.2. Buttons ....................... 3.1.3. The reveal/hold info box ...... 3.1.4. The window icons .............. 3.1.5. The main window ............... 3.1.6. The mouse cursor .............. 3.2. More windows ......................... 3.3. The menu bar ......................... 3.3.1. The DESK title ................ 3.3.2. The CONTROLS title ............ 3.3.3. The WINDOWS title ............. 3.3.4. The PRINT title ............... 3.3.5. The REFRESH title ............. 3.3.6. The MISC. title ............... 3.3.6.1. Show Control Bits .... 3.3.6.2. Background Memory .... 3.3.6.3. Source ............... 3.3.6.4. Hardware Interface ... 3.3.6.5. Help ................. 3.3.7. The STORAGE title ............. 3.3.8. The QUIT title ................ 3.4. Keyboard entry ....................... 4. Last Note ................................. PROGRAM DESCRIPTION =================== 1. Preface ========== With the program 'TXT' it is possible to control a teletext decoder. (Teletext = Videotext = Ceefax = Skytext = Supertext = etc.) Pages can be selected and viewed on the Atari high resolution screen. (HiRes only) The contents of the pages can be stored on disk for reading later on. (Or to be used in another program) 2. Hardware =========== The hardware needed is a normal CCT decoder and a little interface. CCT stands for 'Computer Controlled Teletext'. A standard CCT decoder consists of the following main components: The CCT-chip, The VIP2-chip (Video Input Processor) and a 1k8 static RAM (Page memory). The CCT-chip (SAA5240) and VIP-chip (SAA5230) are chips from PHILIPS-Elcoma. For an application diagram see the data sheet of the CCT. It is also possible to use an existing CCT-decoder. All you have to do is disconnect the 2 I2C lines from the controlling microprocessor and connect these wires to the interface. A drawing of the interface can be found in the TXT program itself. (Menu title: Misc; Entry: Hardware interface...) 3. Operating the TXT program ============================ 3.1 What is on the desk After having started the program the following items are on the desk: 3.1.1. The selection box: In the selection box you can see what page you are currently selecting. When you have completed the pagenumber the page is automatically looked for. When subcode entering is selected the symbol SUB is highlighted. Completing the subcode automatically starts the acquisition for that page. Note: The selection box itself is an indicator, not a selectable object. 3.1.2. Buttons: These are selectable items. They are primary intended to control page selection. The digits are used for pagenumber or subcode entering. The arrow left decrements the pagenumber by 1, the arrow right increments the pagenumber by 1. The button on the lower left is used to toggle pagenumber/subcode entering. The question mark button toggles the reveal mode (see below). The button on the lower right is used to put a page on hold (see below). The little character in the box indicates the corresponding key on the keyboard. 3.1.3. The reveal/hold info box: In this box information is given about the reveal and hold status. -Reveal: When reveal is on, the page will be shown on the Atari screen with hidden (concealed) characters displayed. This can be used for puzzles etc. -Hold: When a page is on hold, no updating of the page will occur. This can be used to stop a rolling page. (Note: Loading a page from disk puts the current page on hold to prevent overwriting of the main window with the just loaded page). Note: This box is an indicator and cannot be selected with the mouse. 3.1.4. The window icons: These are 4 selectable icons. Selecting one of these icons has the following effect: When the corresponding window is open this window becomes the window on top. When the corresponding window is not open, the window will be opened. Furthermore it is possible to drag the main window icon to the icon of window A,B or C. Then the contents of the main window will be copied to window A,B or C respectively. 3.1.5. The main window: When you have waited long enough, the main window will be filled with page 100. (Index page) This window can be moved according to the normal rules. Closing the main window quits the program. The topline of the main window contains the pagenumber and subcode of the page currently in acquisition. The pagenumber and subcode are separated with the subcode symbol. When a requested page is received, the page will be displayed in the main window. When a page is loaded from disk it will be displayed in the main window. Regardless whether the main window is on top or not. 3.1.6. The mouse cursor. Normally the mousecursor is a solid arrow. While downloading a page, user controls are postponed. This is indicated with an open arrow. 3.2. More windows It is possible to have multiple windows on the screen. The TXT program allows to have up to 4 windows simultaneously opened. Desk accessories, however, can open more windows. E.g. the control panel can be open during the operation of the TXT program. The normal window controls apply here. Note: Closing the main window quits the program. 3.3. The menu bar Except for the digits the menu bar contains all controls for the TXT program. 3.3.1. The DESK title: The desk title contains the usual desk accessories and the entry About 'TXT'.... Selecting this entry shows a dialog box that gives information about the version of the program, the author and the system with which the program was developed. Furthermore this the message Public Domain Software is given. So this program is free for non commercial use. 3.3.2. The CONTROLS title: This menu title contains the same entries as can be selected from the desktop. The characters preceding ')' gives the corresponding keyboard input. 3.3.3. The WINDOWS title: Here the window controls can be found. No further explanation necessary. Again the character preceding ')' gives the corresponding keyboard entry. 3.3.4. The PRINT title: The entries of the PRINT menu are used to print things on a printer. Print Main Window, Print Window A, Print Window B and Print Window C are used to send the contents of the corresponding window to the printer. Print Screen gives a dump of the screen (as Alternate/Help). Print New-Line sends a carriage-return line- feed to the printer. Print Form-Feed sends a form-feed to the printer. With Pr. Dual-Density and Pr. Normal-Density you can select the bitimage mode that will be used to print the windows. Normal density has a better aspect ratio. The dual density bitimage mode gives better readable characters. (Dual density: ESC L; Normal density: ESC K) 3.3.5. The REFRESH title: The Refresh Header entry, gives the possibility to download the header (containing the time) and display it in the main window. The Refresh Total Window option can be used when the page has not been received correctly. The whole page is downloaded and displayed in the main window. 3.3.6. The MISC. title: In the MISC title menu the following entries can be found: 3.3.6.1. Show Control Bits... The Show Control Bits entry shows a dialog box with the values of the control bits of the page that has been received. The meaning of the bits are only significant for someone who wants to know how teletext is broadcasted. An explanation of the control bits is beyond the scope of this document. 3.3.6.2. Background Memory... The Background Memory... entry selection shows a dialog box. You are requested whether your text decoder (hardware) has a background memory or not. Using a text decoder with a background memory reduces the time to wait for a page, to practically zero. 3.3.6.3. Source... Selecting the Source... entry gives information how to get the source of this program. The source can be useful for Modula-2/ST programmers. If you want to get a copy of the source of this program, please read the file SOURCE.TXT. 3.3.6.4. Hardware Interface... Selecting the Hardware Interface... entry gives a diagram of the hardware interface between the text decoder and the Atari-ST. 3.3.6.5. Help... Selecting Help... gives information about the keyboard entry. Keyboard entry is sometimes easier than entry using the mouse. Especially for digit entry. 3.3.7. The STORAGE title: This menu title contains selections for storing (Save main page..., Save page A... etc.) and retrieving (Load page...) pages from disk. Furthermore it is possible to delete files from disk (Delete file...). After selection of one of the entries, the standard fileselector box appears with additional information about what to do with the selected file. The character preceding the ')' denotes the corresponding keyboard entry. Note: The page files are character files. The page is stored as 1000 characters (25 lines of 40 characters). No carriage-returns or line-feeds are used. The same character codes are used as the CCT-chip does. First the actual page is written (starting with the header). After that the so called status line is written (topline of the window). Note: The drive keeps on turning a little longer than normal after a disk access. This is normal. 3.3.8. The QUIT title: Selecting Ok quits the program. Note: Closing the main window or selecting 'Q' on the keyboard also quits the program. 3.4. Keyboard entry The following keys are defined: 0..9: Digits. Used to select a page (with or without subcode). -: Decrement page number by 1. +: Increment page number by 1. ?: Reveal/Conceal toggle. The page is downloaded using the new state of reveal. A: Open window A or window A on top. B: Open window B or window B on top. C: Open window C or window C on top. D: Delete a file. Select a file using the fileselector box. H: Toggle the hold page status. L: Load a page from disk. Select a file using the fileselector box. M: Main window on top. Q: Quit. S: Toggle subcode entry / pagenumber entry F1: Copy contents of main window to window A. When window A is not open it is opened. F2: Copy main window to window B. F3: Copy main window to window C. F4: Close window A. F5: Close window B. F6: Close window C. F7: Save contents of window A to disk. Select a file using the fileselector box. F8: Save window B on disk. F9: Save window C on disk. F10: Save contents of the main window to disk. HELP: Shows a help screen. 4. Last note ============ I have written this program for my pleasure in the first place. Maybe some functions are not as logical as you would expect. It is even possible that bugs are in the program. There is always a fool that can make the program crash. When the program crashes remember: the program was free. V2.0 01-May-87, * First documented public domain release. V2.0a 11-Dec-88, * Error in interface diagram corrected, * No LCD digits in selection box, so that now the program can be run from the GEM 2.2 desktop. (GEM 2.2 is a complete GEM implementation for the Atari-ST by ABC- Software, Bruchem, The Netherlands) * Minor changes in the documentation. (C) Harrie F.A. de Leeuw, Papaverstraat 24, 5271 RB Sint-Michielsgestel, The Netherlands.