28128 Parallax Inc, 28128 Datasheet - Page 55

• 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

Electronics designers use data sheets to find the kind of information just discussed. Each
IC manufacturer publishes data sheets for the integrated circuits they make. The
information just covered on the pin map and control signals was condensed from a data
sheet published by National Semiconductor, the maker of the ADC0831. Of course all of
the datasheets are available on the manufacturer's web sites.
Build It
Figure 3-3 shows the schematic for this experiment. This is a fairly simple circuit to
build, so let's try it without the breadboard example. Hopefully you're getting the hang of
the list of connections described by a schematic. Remember, when working with the
connections to an IC, use the index mark on the chip along with the pin map to figure out
the pin numbers!
Program It
Program Listing 3.1 is the first step to a functional DC voltmeter. This program displays
the 8-bit serial output of the ADC0831. Enter the code and save it as P3_1R0.bs2. There
will be three revisions of this program listing, so it will become important to keep track
of your source code versions.
P0
P1
P2
1
7
6
Vdd
/CS
CLK
D0
ADC0831
8
Vdd
Vref
5
Vin(+)
GND
Vin(-)
2
4
3
Vss
Vdd
Vss
100 kΩ
Pot
Figure 3-3
Schematic
List of connections made on this
schematic:
Pin 1 on the ADC0831 is connected to pin
P0 on the BASIC Stamp.
The wiper terminal of the pot is connected
to pin 2 on the ADC0831.
Of the two remaining terminals on the pot,
one is connected to Vdd on the Board of
Education, and the other is connected to
Vss.
Pins 3 and 4 on the ADC0831 are
connected to Vss.
Pins 5 and 8 on the ADC0831 are
connected to Vdd.
Pins 7 and 6 on the ADC0831 are
connected BASIC Stamp pins P1 and P2
respectively.