28122 Parallax Inc, 28122 Datasheet - Page 156

• Manufacturer Part Number: 28122
• Description: KIT WHAT'S A MICRO:PARTS ONLY
• Manufacturer: Parallax Inc

Specifications of 28122

• Accessory Type: Parts Kit
• Product: Microcontroller Accessories
• Core Processor: PIC16C57c
• Flash: 128 Bytes
• Operating Supply Voltage: 9 V
• Board Size: 31 mm x 16 mm
• For Use With/related Products: Board of Education Full Kit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

discharges as it feeds current through the resistor. As the capacitor discharges, the
voltage across its terminals gets lower and lower (decays).
Back in the pushbutton chapter, you used the BASIC Stamp to detect a high or low signal
using the variables
low signal was considered Vss. It turns out that a high signal is any voltage above 1.4 V.
Of course, it could be up to 5 V. Likewise, a low signal is anything between 1.4 V and 0
V. This
which indicates that the capacitor voltage decayed below 1.4 V.
The result is then displayed and the program ends.
Your Turn – A Faster Circuit
By using a capacitor that has roughly 1/3 the capacity to hold charge, the time
measurement for each resistor value that is used in the circuit will be reduced by 1/3. In
Activity #3, you will use a capacitor that is 10,000 times smaller, and the BASIC Stamp
will still take the time measurements for you using a command called
√
√
√
√
INPUT 7
DO
LOOP UNTIL IN7 = 0
DEBUG CR, CR, CR, "The RC decay time was ",
END
DO…LOOP
Disconnect power to your Board of Education or HomeWork Board.
Replace the 3300 µF capacitor with a 1000 µF capacitor.
Confirm that the polarity of your capacitor is correct.
terminal should be connected to Vss.
Reconnect power.
PAUSE 100
timeCounter = timeCounter + 1
DEBUG ? IN7
DEBUG DEC5 timeCounter, CR, CRSRUP, CRSRUP
DEC timeCounter, CR,
"tenths of a second.", CR, CR
checks P7 every 100 ms until the value of
IN3
and
IN4
. At that time, a high signal was considered Vdd, and a
IN7
changes from 1 to 0,
RCTIME
The negative
.