28123 Parallax Inc, 28123 Datasheet - Page 85

• 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

Figure 3-7 shows what the BASIC Stamp sees when the button is pressed, and when it’s
not pressed. When the pushbutton is pressed, the BASIC Stamp senses that Vdd is
connected to P3. Inside the BASIC Stamp, this causes it to place the number 1 in a part
of its memory that stores information about its I/O pins. When the pushbutton is not
pressed, the BASIC Stamp cannot sense Vdd, but it can sense Vss through the 10 kΩ and
220 Ω resistors. This causes it to store the number 0 in that same memory location that
stored a 1 when the pushbutton was pressed.
P3
220
Ω
Vss
10
kΩ
Vdd
P15
P14
P13
P12
P11
P10
P9
P8
P7
P6
P5
P4
P3
P2
P1
P0
X2
X3
Vdd
Vin
Vss
Figure 3-6
Pushbutton Circuit
Connected to I/O Pin
P3
On the wiring
diagram, the 220
resistor is on the left
side connecting the
pushbutton to P3
while the 10 k
resistor is on the
right, connecting the
pushbutton circuit to
Vss.
Ω
Ω