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EE Design > In Technical | Home | Contact | Title: Expanding Analog Inputs using analog multiplexers Author: Vincent Wong Date: 29th March 2005 It is often to expand analog channels using an analog multiplexers. In the PIC micro, there is also an 8-bit analog multiplexer. However, in most case, 8 analog channels are not sufficient enough e.g. for scanner boards. Expanding Analog Inputs using analog multiplexers The RA0 pin is set as in analog input of the PIC micro. The analog multiplexer's COM pin (COMMON) is connected to the analog input. RA1-RA3 connects to A0-A2 control lines, to select which channel to read (NO1-NO8). RA4 is used to enable/disable the analog multiplexer. Note that the RA4 is being pulled up because it is an open collector pin. To multiplex a 16-channel analog multiplexer the MAX396 or DG406 can be used. They now have 4 control lines to select 1-of-16 channel analog input. | Home | Top Page | Contact | Copyright Notice: This article, including all text, documents and schematic diagrams, are the intellectual property of Vincent Wong, and is Copyright (c) 2005. Reproduction or re-publication by any means whatsoever, whether it is electrical & electronic, mechanical or electro-mechanical, is strictly prohibited under International Copyright laws. The author (Vincent Wong) grants the reader the right to use this information for personal use only. Commercial use is prohibited without express written authorisation from Vincent Wong. Copyright of Vincent Wong. All Rights Reserved.