DATA_ENTRY_KEYPAD_ENCODER

Published:2009/7/11 3:59:00 Author:May | From:SeekIC

Designed for use in point-of-sale and other data-entry applications requiring bounceless binary encoder.Keypad is scanned by CD4067 16-channel analog multiplexer. When key is depressed, appropriate channel is driven low. When counter ad-dresses low input of multiplexer, common output goes low for one clock cycle. Differentiating network changes this to negative spike for strobing counter data into quad latch where it remains until another key is depressed clockshould be above 200 Hz．－M. E.κeppel, Multiplexer Scans Keyboard for Reliable Binary Encoding, Electronics, March 17,1977,p 99.



Reprinted Url Of This Article:
http://www.seekic.com/circuit_diagram/Measuring_and_Test_Circuit/DATA_ENTRY_KEYPAD_ENCODER.html

Print this Page | Comments | Reading(3)