titus-larsen-titus-1981-apple-interfacing

e has been divided into 256 values, or 255 steps, the voltage inent
available is:
10 volts I 255 steps = 39 millivolts/ step
can probably write a short program that would increment an
ount and output it to the DA converter. Don't worry about the
nal operation of the D/ A converter, just treat it like an output
, Your program will generate a slowly increasing positive voltramp.
Develop your program in the space below:
. FOR V = 0 TO 255
POKE 43918,V
NEXT V
c GOTO 10
'Simple voltmeter or volt-ohm-rnilliammeter ( vom) may be used
onitor the voltages. Connect the meter between ground and the
18 VDAC output ( VDAC is positive). Try your program. Does
oltage increase slowly What happens when the voltage reaches
t + 10 volts
voltage increases slowly to + 10 volts. When it reaches this
e, it quickly changes to zero volts, or ground, and it starts to
ase slowly once again.
u can slow the voltage ramp by introducing a short time delay
·
in your program. We used the following:
= 0 TO 100: NEXT T
evelop a program that will generate a negative-going ramp, and
that will generate a triangular ramp (slow-up then slow-down).
·used the following programs:
e •mp
FOR V = 255 TO 0 STEP -l