pruss for ppm/pwm realtime decoding

I’m interested in adding wwvb radio clock capabilities to the beagle bone in one project and have another that needs to decode a pwm or ppm stream. For the wwvb radio clock application the pulses have an interval of 1 second, starting low for 200ms, 500ms, or 800ms, followed by a high state of 800ms, 500ms, or 200ms respectively (high state + low state = 1second) with each pulse representing a 0, 1, or marker. The other application needs to decode a pwm or ppm signal in which a series of binary multibit numbers are included in the width and or position of each pulse. could the pruss be used to decode these streams in realtime then asert an nmi such that linux kernel and/or userspace immediately reads in and acts upon the values read. Are there any good examples of this or similar use of the pruss? can the pruss even do such a task?

Eric

Hi Eric,
Sure you can use Pruss for this. The pruss ruan at 200mhz,. I used Pruss to decode signal from receiver, the pulse is about 1.5ms and it can gain 512 level for 11 channels.

Xu

Hello Xu!
I am trying to do the exact same thing: I want to read an rc receiver using the beaglebones pru.
I did this succesfully before using the arduino by attaching a couple of interrupts. Now I want to do it with the beaglebone.
Can you push me in the right direction on this?? I need to do a lot of real time processing for my latest project.
Any reading you can reconmend for me? Would you be willing to share some of your code?
I found a couple of online libraries, but I am not yet that proficient with C, but I do know C++

http://elinux.org/ECE497_BeagleBone_PRU#Installation_Instructions

http://hipstercircuits.com/?p=349

Hi Eric,
I start Pru from the first link you sent. I put hte source code of my project to here.
http://code.google.com/p/beagle-fly/downloads/detail?name=v_0.0.1.zip&can=2&q=#makechanges

Please refer the code in ReadPWM for source code. It include test code also.
Hope this could help.
Thanks,
Xu

Hi Brett,
I start Pru from the first link you sent. I put hte source code of my project to here.
http://code.google.com/p/beagle-fly/downloads/detail?name=v_0.0.1.zip&can=2&q=#makechanges

Please refer the code in ReadPWM for source code. It include test code also.
Hope this could help.
Thanks,
Xu

Any update on that? I’m trying to port the receiving portion of rc-switch to BeagleBoard for RF data collection. I’m looking at a way to quickly decode the RF wave, and it looks like PRUSS is the way to go. Anybody already have this working?

Thanks!

I will try to update it this weekend for both beaglebone and beglebone black