Renesas M16C 62p for universal remote

Thread Starter

Firestorm

Joined Jan 24, 2005
353
Hey all,

I'm working on a simple universal remote using the M16C. I only want it to control up to 4 devices and just do 3 options (toggle power, channel up, channel down) since I only have 3 buttons on my dev board.

My question is with the IR led. I know that most remotes operate on a 40kHz carrier frequency, which can be interrupt driven probably. Using the serial port (TX), how would I hook up the IR led and send the signals for each option? Any help is much appreciated!

Thanks
 

Papabravo

Joined Feb 24, 2006
12,931
The serial port is not likely to be much use in an IR application. In most IR protocols the 1's and 0's take different amounts of time to generate. In the NEC protocol that we use in our products each bit starts with a carrier burst @ 38 kHz of 560 microseconds. This is followed by 565 microseconds of silence (no carrier), or 1690 microseconds of silence. A complete message is 32 bits that consists of 16 bits of data and the 1's complement of that data so that each 32 bit message takes the same length of time because it has exactly the same number of 1's as 0's

I have found the following pages helpful:
http://www.sbprojects.com/knowledge/ir/nec.htm
 

Thread Starter

Firestorm

Joined Jan 24, 2005
353
Thanks for the information Papabravo. We might be switching gears on our project if this one doesn't take hold soon. We have to use serial communication in our project, and thought we could just output the code via serial port. Another option we thought would work would be a photoled to read in the code, and then store it. Then output it for the final application. If you have any more pointers or advice, I'd really like to hear them.
Thanks again!
 

Papabravo

Joined Feb 24, 2006
12,931
Universal remotes like the Philips Pronto can actually be configured to use any protocol you care to specify. With one of them you could prototype the device you intend to build so that whoever is working on the other end can have a remote up and working in about an hour. They are pricey, but they are an invaluable development tool. Send me a PM if you need some prfessional help -- I may have some bandwidth available.
 

ELECTRONERD

Joined May 26, 2009
1,147
Ironically I was just looking at my M16C demo board today, but I don't know anything about it. Haven't messed around with it yet. I did, however, program these two LEDs to alternate and whose speed depended on light measured by a CdS cell. It was a sample program, though.

Austin
 

Thread Starter

Firestorm

Joined Jan 24, 2005
353
Would my logitech harmony remote do the trick? I'm wanting to use the m16C as the remote (use the 3 buttons on the board). Just need to figure out what gets sent to the board.
 

Thread Starter

Firestorm

Joined Jan 24, 2005
353
After talking with my professor about the project, we decided this was too complicated for what he wanted use to accomplish in just a couple of weeks, so we have switched directions to a serial connected baseball scoreboard. Thanks for all the helpful insight on this, it was still good to learn alot about IR.
 
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