Brian Lewis shows you in detail how this keyboard organ program and ASCII generator works, cross refer to your user manual This program demonstrates many of the Amstrad's advanced features while giving a useful insight into the inner workings of ASCII code. It's a keyboard organ program and ASCII generator. The program is split into two parts: lines 100 to 280 produce the first screen, and by pressing any key — excluding break — a musical note and the ASCII code associated with it arc produced. When more than 50 notes are sounded, part two of the program (lines 290-530) plays all 50 notes consecutively with three voices. Note: All variables have been printed in lower case. Both loops have been indented by four spaces. If more than one space is left, it is specified. This has been done so that you can follow the program more easily and it is recommended that it is adopted as a standard on all Amstrad public domain programs. How it works Cross-refcrences are to Amstrad user manual - 100 Defint ch 8, p 10: sets all variables to integer values to save memory. Try replacing Defint with Def real and run program by escaping out and print Fre(“”) to see memory saving
- 110 Zone ch 8, p 53; ch 3. p 6: changes print zone width, i.e. sets comma tab stops to column 0,10,20,30 etc when using zone 10
- 130 Every ch 8, p 17: timing command used for printing in window #2. Every 100 = 2 seconds. See also lines 500-530
- 140 Mode ch 8, p 28: mode 0 = 20 columns, mode 1 = 40 columns, mode 2 = 80 columns
- 160-170 Window ch 8, p 52: screen window command. Line 160 opens a window in screen centre and scrolls the ASCII code independently of rest of screen. Line 170 opens a window at bottom right of screen only and displays, in this example, lines 500-530 • Amendment to book, ch 8, p 52: example should include 41, 10,30.7,18
- 180-200 Pen ch 8, p 34: sets pen for window 1 to ink 1. pen for window 2 to ink 1. No ink command is issued so ink 1 is default colour yellow. • Amendment to book ch 8, p 34: example should read Pen #1,2 not Pen 1,2
- 210-280 While, Wend ch 8, p 51: loop commands which terminate when a command is true, i.e. b X50 • Amendment to book appendix III, page 1: ASCII characters should read DEC 1 = CTRL(A), DEC 2 = CTRL(B)
- 290 return to mode 1, 40 column screen
- 300-340 two windows arc used again but with different colours. In this mode there is a choice of four out of a possible 27. Try listing in #1 or #2, i.e. type LIST #1 to see what happens after escaping out of program. Window #1 is ink 3, window #2 is ink 2 so defaulting to red and light blue
- 360 ensures that keyboard buffer is flushed during execution of program
- 350-390 plays all 50 notes consecutively with the lower and higher overtones purposely out of synchronization, to give a feeling of life and movement. Try putting voices back into synchronization for comparison or use envelopes for more sophisticated sounds. Ch 6, p 8
- 400 prints ASCII code for all three voices
- 410-430 Sound: defaults to value 4 if not specified. Max number is 7 if no envelope is used. Compare lines 410 to 420,430
- 440-460 plays the notes and then starts again with screen 1
- 500-530 prints these messages alternatively in the #2 window
Home Computing Weekly #87 | ★ AMSTRAD CPC ★ DOWNLOAD ★ |
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CPCrulez[Content Management System] v8.7-desktop/c
Page créée en 471 millisecondes et consultée 1474 foisL'Amstrad CPC est une machine 8 bits à base d'un Z80 à 4MHz. Le premier de la gamme fut le CPC 464 en 1984, équipé d'un lecteur de cassettes intégré il se plaçait en concurrent du Commodore C64 beaucoup plus compliqué à utiliser et plus cher. Ce fut un réel succès et sorti cette même années le CPC 664 équipé d'un lecteur de disquettes trois pouces intégré. Sa vie fut de courte durée puisqu'en 1985 il fut remplacé par le CPC 6128 qui était plus compact, plus soigné et surtout qui avait 128Ko de RAM au lieu de 64Ko. |
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