122-28176 Parallax Inc, 122-28176 Datasheet - Page 86

• Manufacturer Part Number: 122-28176
• Description: GUIDE STUDENT PROCESS CONTROL
• Manufacturer: Parallax Inc

Specifications of 122-28176

• Accessory Type: Manual
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: Propeller Education (PE) Kit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant

Other devices may simply output a digital HIGH and LOW. If the device does not use
the same supply, ensure that output voltages are compatible with the BASIC Stamp. If
the switch is powered from another supply, the grounds will need to be connected
together. Figure 3-22 and Figure 3-23 illustrate various methods of interfacing digital
devices.
Figure 3-22 (top): TTL and CMOS logic inputs powered from a +5 volt supply can be
applied directly to the BASIC Stamp input pins. If the two systems are supplied from the
same 5 volts, great. If not, at least the grounds must be common (connected together).
Figure 3-22 (bottom): Low-voltage (+3 V) devices can be interfaced using a 74HCT03,
or similar open-drain devices, with a pull-up resistor to the BASIC Stamp module’s +5
volt supply. Supply the chip with the low-voltage supply and make the grounds common.
Figure 3-22
Digital Interface
Circuits
Top: Standard TTL
to BASIC Stamp
Bottom: Low Voltage
Logic to BASIC
Stamp