Revision Help !!!

[Graham Johnson]

Please could some very kind person out there help me with this
revision question.

Q)What problems can be encountered when using switches as inputs to a
microcomputer and how can these problems be overcome.

 

[Reinhard Zwirner]

Graham Johnson schrieb:

Please could some very kind person out there help me with this
revision question.

Q)What problems can be encountered when using switches as inputs to a
microcomputer and how can these problems be overcome.

Search for "contact bouncing", e.g.

<http://www.elexp.com/t_bounc.htm>

HTH

Reinhard

 

[John Fields]

On Sun, 06 Jun 2004 16:18:06 GMT, graham.johnson10@virgin.net (Graham
Johnson) wrote:

Please could some very kind person out there help me with this
revision question.

Q)What problems can be encountered when using switches as inputs to a
microcomputer and how can these problems be overcome.
---

A1. Since an open switch presents a nearly infinite impedance to an
input, allowing the input to float (no pullup or pulldown resistor)
can/will cause problems.

A2. Switches bounce on make and on break, so unless either hardware or
software debouncing is done, problems will occur because of the
multiple makes/breaks which will happen when the switch is exercised.

--
John Fields