28128 Parallax Inc, 28128 Datasheet - Page 64

• Manufacturer Part Number: 28128
• Description: KIT BASIC ANALOG/DIGI PARTS ONLY
• Manufacturer: Parallax Inc

Specifications of 28128

• Accessory Type: ADC, DAC
• Product: Microcontroller Accessories
• For Use With/related Products: BASIC Stamp® 2 and Board of Education
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Calculate Voltage
Now that we know the decimal equivalent of the ADC0831’s binary output, we can do a
few calculations to get the measured voltage. To find out what voltage the decimal
number corresponds to, we need to calculate where in the voltage range the number falls.
Here is an effective way to think about the problem.
This translates to fractions as:
We can re-arrange this equality to calculate the voltage:
•
•
We know that the voltage is on a 0 to 5 volt scale, and we know that the
ADC0831’s output is on a scale from 0 to 255.
In other words, the measured voltage is to 5 as the A/D output is to 255.
Voltage=
Voltage
5
=
5
Decimal
×
(Decimal
A
255
255
/
A/D
D
Output
Output)
Figure 3-6
Debug Terminal
Output for Program
Listing 3.1,
Revision 1.