28123 Parallax Inc, 28123 Datasheet - Page 55

• 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

Your Turn – Modifying the LED Test Circuit
In the next activity, you will program the BASIC Stamp to turn the LED on, then off,
then on again. The BASIC Stamp will do this by switching the LED circuit between two
different connections, Vdd and Vss. You just finished working with the circuit where the
resistor is connected to Vdd, and the LED emits light. Make the changes shown in Figure
2-9 to verify that the LED will turn off (not emit light) when the resistor’s lead is
disconnected from Vdd and connected to Vss.
ACTIVITY #2: ON/OFF CONTROL WITH THE BASIC STAMP
In Activity #1, two different circuits were built and tested. One circuit made the LED
emit light while the other did not. Figure 2-10 shows how the BASIC Stamp can do the
same thing if you connect an LED circuit to one if its I/O pins. In this activity, you will
connect the LED circuit to the BASIC Stamp and program it to turn the LED on and off.
Vss
√
√
√
√
470
Disconnect power from your Board of Education or HomeWork Board.
Unplug the resistor lead that’s plugged into the Vdd socket, and plug it into a
socket labeled Vss as shown in Figure 2-9.
Reconnect power to your Board of Education or HomeWork Board.
Check to make sure your green LED is not emitting light. It should not glow
green.
Ω
Vss
LED
P15
P14
P13
P12
P11
P10
P9
P8
P7
P6
P5
P4
P3
P2
P1
P0
X2
X3
Vdd
Vin
+
Vss
Figure 2-9
LED Off Circuit
Schematic (left) and
wiring diagram (right).