RPi Tutorial EGHS:Shift Registers

From eLinux.org
Revision as of 10:40, 27 February 2012 by Meltwater (Talk | contribs)

Jump to: navigation, search

Back to the Hub, or the Tutorials page.


GPIO Hardware & Software Tutorials:


This page is part of a work in progress.

Warnings

While most of these circuits may interface directly to the RPi, the use of a buffered interface (such as the one supplied by the Gertboard) is recommended which will help protect against damage. Alternatively, experiment with one of the Alternative Test Platforms.


Extreme caution should be exercised when interfacing hardware at a low level, you may damage your RPi, your equipment and potentially yourself and others. Doing so is at your own risk!

Aims

Considering the following site, Arduino - Parallel to Serial Shifting-In with a CD4021BE contains all the required information, there is little need to repeat it all here. The main thing is that the circuit works fine using a 3.3V supply and logic levels, so the components should be suitable for use with the RPi (and TI LaunchPad).

Note:
Until RPi devices are available, I can not confirm this will work on a real RPi.
For now, I shall be using the TI LaunchPad (see  Alternative Test Platforms
for details) to test the hardware on (as it is cheap and the logic levels similar).

The Hardware

Theory

Circuit

The Software

While the RPi is not available, I can only confirm the TI LaunchPad code works for me.

TI LaunchPad

Sample test code for shift register input (tested on TI MSP430G2553 device).

Circuit

Code:

RPi

References