PET Metronome

Elizabeth Deal

The Pet can double as the most expensive metronome in the world at no additional cost other than typing seven lines of code. Register 59468 (the same one that controls graphic or lower case mode) is used to produce clicking sounds which are heard through a speaker-amplifier connected to the user port. The usual "music" connection is required via pins M and N of that port.

The instruction for using the gadget are in the REM lines. The program begins clicking at the rate of 120 beats per minute. The rate can be adjusted quickly or slowly by pressing the appropriate keys.

100 J = 3600 : T = 360 : B = 30 : R = 120 : P = 1 : M = 59468 : L = 236 : N = 204 : D = 12 : G = 5 : C = 255 : Q = 64 : H = 10 - P
110 K = 151 : S = 152 : A = 0 : V = 12 : TI$ = "000000"
120 X = TI : PRINT "6" R; TI$ : Z = PEEK(K) : F = PEEK(S) : I = P + F * H : IFZ = QTHENPOKEM, V : END
130 R = R - I * (Z = D) + I* (Z = G) : R = R + (R - T) * (R>T) + (R - B) * (R>B) : IFZ<> CORF <> AGOTO120
140 POKEM, N : POKEM, L : W = J/R
150 IF (TI - X) <WGOTO150
160 GOTO120
170 REM===============================
180 :           PET METRONOME
190 : ELIZABETH DEAL, MALVERN, PA 19355
200 REM===============================
210 RATE IS SHOWN IN BEATS PER MINUTE
220 < > FOR SLOW CHANGE IN RATE
230 SHIFTED < > FOR FAST CHANGE
240 Q TO QUIT & RESET REGISTER
250 T AND B GIVE RANGE OF RATE, B>0
260 MAX RESOLUTION 7 - 8 JIFFIES
270 MAX ERROR 0.6 JIFFIE/BEAT, I THINK.
280 :	(LINE 160 IS NOT TIMED)
290 FOR USE AN ACCURATE LONG TERM
300 COUNTER SET RATE 1% LOWER THAN
310 DESIRED.
320 :	REL. 2 PETS - K = 515, S = 516