di2536l2.txt
;***************************************************************************************************
; LISTING 2 - DISPLAY PROGRAM FOR SAMPLED WAVEFORMS
;
; "Use a PC to record four-channel waveforms," EDN, May 25, 2000, pg 116
;
; http://www.ednmag.com/ednmag/reg/2000/052500/designideas.htm#11di3
;***************************************************************************************************

KEY 20, CHR$(0) + CHR$(72):    ON KEY(20) GOSUB UpLine
KEY 21, CHR$(0) + CHR$(80):    ON KEY(21) GOSUB DownLine
KEY 15, CHR$(0) + CHR$(73):    ON KEY(15) GOSUB UpPage
KEY 16, CHR$(0) + CHR$(81):    ON KEY(16) GOSUB DownPage
KEY 22, CHR$(0) + CHR$(75):    ON KEY(22) GOSUB Left
KEY 23, CHR$(0) + CHR$(77):    ON KEY(23) GOSUB Right
KEY 17, CHR$(0) + CHR$(1):     ON KEY(17) GOSUB Finish

SCREEN 12
DIM chr AS STRING * 1
DIM prv(3) AS INTEGER
DIM ptr AS LONG
OPEN "samsig.dat" FOR BINARY AS #1
 GET #1, 1, chr: lo% = ASC(chr) MOD 16
 FOR k% = 0 TO 3
  prv(k%) = lo% MOD 2: lo% = lo% \ 2
 NEXT k%
 d% = 12: dd% = 16: fl% = 0: ptr = 0
 KEY(17) ON

WHILE fl% = 0
 KEY(15) ON: KEY(16) ON: KEY(20) ON
 KEY(21) ON: KEY(22) ON: KEY(23) ON
 LOCATE 1, 36: PRINT ptr
 FOR i% = 0 TO 255: FOR j% = 0 TO 128: NEXT j%
 NEXT i%
 KEY(15) STOP: KEY(16) STOP: KEY(20) STOP
 KEY(21) STOP: KEY(22) STOP: KEY(23) STOP
 FOR i% = 0 TO 4
  y% = i% * 96 + 32
  FOR j% = 1 TO 320
   GET #1, ptr + j% + i% * 320, chr
   lo% = ASC(chr) MOD 16: hi% = ASC(chr) \ 16
   x% = 2 * j%
   FOR k% = 0 TO 3
    IF prv(k%) <> lo% MOD 2 THEN
     LINE (x%, y% + k% * dd%)-(x%, y% + k% * dd% + d%)
    ELSE
     IF (lo% MOD 2) THEN
      PSET (x%, y% + k% * dd%)
     ELSE PSET (x%, y% + k% * dd% + d%)
     END IF
    END IF
    prv(k%) = lo% MOD 2: lo% = lo% \ 2
   NEXT k%
   x% = x% + 1
   FOR k% = 0 TO 3
    IF prv(k%) <> hi% MOD 2 THEN
     LINE (x%, y% + k% * dd%)-(x%, y% + k% * dd% + d%)
    ELSE
     IF (hi% MOD 2) THEN
      PSET (x%, y% + k% * dd%)
     ELSE PSET (x%, y% + k% * dd% + d%)
     END IF
    END IF
    prv(k%) = hi% MOD 2: hi% = hi% \ 2
   NEXT k%
  NEXT j%
 NEXT i%
WEND
 KEY(15) OFF: KEY(16) OFF: KEY(20) OFF
 KEY(21) OFF: KEY(22) OFF: KEY(23) OFF
CLOSE #1
END

UpLine:
 IF ptr < 61120 THEN
  CLS 1: ptr = ptr + 320
 END IF
RETURN
Left:
 IF ptr < 61440 THEN
  CLS 1: ptr = ptr + 1
 END IF
RETURN
UpPage:
 IF ptr < 59840 THEN
  CLS 1: ptr = ptr + 1600
 END IF
RETURN
DownLine:
 IF ptr >= 320 THEN
  CLS 1: ptr = ptr - 320
 END IF
RETURN
Right:
 IF ptr >= 1 THEN
  CLS 1: ptr = ptr - 1
 END IF
RETURN
DownPage:
 IF ptr >= 1600 THEN
  CLS 1: ptr = ptr - 1600
 END IF
RETURN
Finish:
 fl% = 1
RETURN