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Graphic Editor: Analog Keyboard Encoder

This design example allows you to decode a large number of switches in a keypad or keyboard with only two I/O pins and a GND pin using Altera® MAX® II devices.

The circuit in Figure 1 shows how an Altera EPM570-T100 (along with an external capacitor) can utilize its internal oscillator, Schmitt trigger I/O, and high-density arithmetic programmable logic fabric to replace an A/D converter to decode an analog switch array.

Download the analog keyboard encoder graphic editor files.

Figure 1. Block Diagram for Two Wire Keypad Decode Using MAX II Devices

Figure 1. Block Diagram for Two Wire Keypad Decode Using MAX II Devices
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For more information on using this example in your project, go to:

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