28123 Parallax Inc, 28123 Datasheet - Page 277

• Manufacturer Part Number: 28123
• Description: TEXT WHAT'S A MICROCONTROLLER
• Manufacturer: Parallax Inc
• Type: Programmingr

Specifications of 28123

• Style: Book
• Title: What's a Microcontroller?
• Contents: Whats a Microcontroller? Text
• Product: Microcontroller Accessories
• Core Processor: PIC16C57c
• Flash: 128 Bytes
• Operating Supply Voltage: 9 V
• Board Size: 31 mm x 16 mm
• Lead Free Status / RoHS Status: Not applicable / Not applicable

Programming Digital Potentiometer Control
Imagine that the knob on the manual potentiometer from the previous exercise has 128
positions. Imagine also that the potentiometer is in the middle of its range of motion.
That means you could rotate the knob one direction by 63 steps and the other direction by
64 steps.
Let’s say you turn the potentiometer’s knob one step clockwise. The LED will get only
slightly brighter. This would be the same as sending a high signal to the AD5220’s U/D
pin and sending one pulse (high-low-high) to the CLK pin.
Imagine next that you turn your manual potentiometer 3 steps counterclockwise. The
LED will get a little bit dimmer. This would be the same as sending a low signal to the
U/D pin on the AD5220 and sending three pulses to the CLK pin.
HIGH 5
PULSOUT 6, 1
LOW 5
FOR counter = 1 TO 3
NEXT
PULSOUT 6, 1
PAUSE 1
P15
P14
P13
P12
P11
P10
P9
P8
P7
P6
P5
P4
P3
P2
P1
P0
X2
X3
Vdd
Vin
Vss
Figure 9-7
Digital
Potentiometer
Controlled
Transistor
Wiring Diagram