Rolling code: Difference between revisions

Revision as of 21:13, 5 June 2013

Revision as of 09:36, 15 August 2013

Line 19:

Remotes control send signals in code. When the sending code is the same as the code which is expected by the receiver, the relay will switch and the door, barrier or car will open. Remote controls with a fixed code will always send out the same code. A rolling code (or hopping code) always send out a different code from the one previously sent. The code changes every time because of the algorithm which is part of the remote control.

== Typical Rolling code System - Keeloq ==

Microchip HCS301 is once the most widely used system on garage and gate remote control and receivers, for example, BFT / ATA / Nice all employs HCS301 keeloq system to encode the transmitter data, we can see the HCS301 keeloq system has 66 data bits which consists of 32 bit serial number and 32 bit rolling data, and other 2 bits are used for additional data on oscilloscope.<ref>[http://blog.solidremote.com/post/hcs301-rolling-code-remote-control-on-oscilloscope.aspx "HCS301 Rolling Code Remote Control on Oscilloscope"]. Solidremote Blogs</ref>

== References ==

{{Reflist}}

*[http://auto.howstuffworks.com/remote-entry1.htm How Remote Entry Works]

* Atmel, Inc.'s application note [http://www.atmel.com/Images/Atmel-2600-AVR411-Secure-Rolling-Code-Algorithm-for-Wireless-Link_Application-Note.pdf AVR411] "describes a Secure Rolling Code Algorithm transmission protocol for use in a unidirectional wireless communication system"