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 Posted: Jun 16, 2012 - 06:28 PM |
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Joined: Apr 02, 2012
Posts: 46
Location: London
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Hi All. I recently got hold of the Atmel Raven kit for cheep (haha) (10.00 pounds!)
I got it because it is a wireless platform and I thought I might be able to use it in a wireless MIDI project. I would like to ask.. Has anyone attempted MIDI or OSC communication with this kit? Or just, would it be possible? I am just starting out with AVR and using an STK500/501 with Atmega16, 32 and 128 devices for programming. If you have experience with AVR Raven wireless transmission and MIDI I would appreciate any advice.
Cheers 4 now,
STeve. |
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Posted: Jun 16, 2012 - 08:22 PM |
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Joined: Apr 15, 2009
Posts: 4861
Location: San Jose, CA
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| It is definitely possible, everything else depends on your skills and time. |
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Posted: Jun 18, 2012 - 08:21 AM |
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Joined: Jun 17, 2008
Posts: 454
Location: Meissen, Germany
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| MIDI - unidirectional 31250 Bit/s is definetely no challenge for Raven and it's friends - so it sounds like an interesting application for µracoli - If you like check out http://uracoli.nongnu.org/buildprocess.html to get started. |
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Posted: Jun 18, 2012 - 09:13 AM |
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Joined: Dec 20, 2002
Posts: 7276
Location: Dresden, Germany
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> unidirectional 31250 Bit/s is definetely no challenge for Raven and it's friends
I'm afraid the more challenging part than just datarate is to keep the latency
low. Of course, this is only important if you want to keep various devices in
sync to each other. I've been told that delays as low as 10 ms are already
quite audible. |
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Jörg Wunsch
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Posted: Jun 18, 2012 - 09:58 AM |
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Joined: Jun 17, 2008
Posts: 454
Location: Meissen, Germany
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> I've been told that delays as low as 10 ms are already
> quite audible.
Of course, to transmit audio data in real time is not a low
brainer. The maximum frame length takes 4.5ms for transmission.
Another point is what to do if a frame gets lost ... some sort of error concealment at the receiving node should be implemented. |
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Posted: Jun 18, 2012 - 05:21 PM |
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Joined: Apr 02, 2012
Posts: 46
Location: London
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alexru wrote:
It is definitely possible, everything else depends on your skills and time.
Time: A lot.(Unemployed University student on vacation)
Skills: Just started learning C and AVR microcontroller programming after some fiddling around with Arduino. Done some interesting experiments with sensors and MIDI and built a rudimentary MIDI to CV shield.
So far with AVR I have managed to hook up an LCD and, using a 4bit LCD library, outputting ascending/descending numbers according to a rotary encoder and a switch. Also read some nice tutorials. The Raven should arrive some time tomorrow.
Thanks for the info and insights... |
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Posted: Jun 20, 2012 - 01:24 AM |
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Joined: Apr 15, 2009
Posts: 4861
Location: San Jose, CA
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I would start from reading datasheets and understanding how radio works. After that, just to get a log of useful experience, I'd start writing my own drivers, without using standard stacks.
If you'll have basic understanding of how radio works, you'll understand how to use stacks in no time. |
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The opinions and views expressed by me on this forum are my own and do not represent my employer or anyone else that I’m affiliated with.
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Posted: Jun 22, 2012 - 05:36 PM |
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Joined: Apr 02, 2012
Posts: 46
Location: London
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Raven Kit arrived this morning AND to my surprise and delight, the package had a boxed AVR dragon in it too! So I bought an AVR Raven Kit and an AVR dragon for 10 pounds! ( about $18.00 ..)
I have managed to get them working ( sort of ) with the USB stick installed and AVR wireless studio reading the temperature, I managed to upload the raven squawk PCM sound file and was succesfully sending messages to the raven boards.
I would like to ask, if I want to learn about programming these modules, does anyone have a good starting point? Alexru mentioned learning about how 2.4 Ghz radio works and building my own drivers.. ( Noob+drivers=??) where to start? |
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Posted: Jun 22, 2012 - 06:51 PM |
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Joined: Jun 15, 2008
Posts: 1756
Location: North Carolina USA
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The original Raven software is kind of cool but you probably can not rebuild it yourself without deleting large chunks to get the 3290p code to fit using gcc. Search the forum for that.
However the 1284p and rf230 SPI-connected radio can be standalone, It is a common and well-tested configuration.
If you want to learn USB study the various USB stick software, e.g. contiki jackdaw or http://www.newae.com/tiki-index.php?page=15dot4tools. |
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Posted: Jun 22, 2012 - 06:59 PM |
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Joined: Apr 15, 2009
Posts: 4861
Location: San Jose, CA
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I personally would start with LCD board and try to send and receive frames from it. "Driver" is just a big word for relatively simple piece of code.
Start by writing simplest program to blink an LED. The only LED on the board is connected to 3290p, and I would not bother trying to work with it for start, so you'll probably have to connect an LED to one of GPIO pins.
Raven is not the most user friendly kit, so prepare to have some minor, but very annoying problems. |
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The opinions and views expressed by me on this forum are my own and do not represent my employer or anyone else that I’m affiliated with.
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Posted: Jun 22, 2012 - 08:59 PM |
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Joined: Jun 15, 2008
Posts: 1756
Location: North Carolina USA
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To clarify, Alex surely means look at the Raven 1284p/rf230 firmware and not the 3290p/LCD firmware, which needs an extra serial command protocol to get anything through wireless.
Contiki cooja is ramping up emulation for the AVRs and now has a Raven mote with 4 virtual LEDs, serial output and a fairly good debugger so you can watch the code scroll by in either assembly or c as the radio is accessed. Radio communication is done at the modem level, scanning over zeroes, start of frame delimiter, packet, checksum. There is a built-in pcap with wireshark export. It's a jump start on 802.15.4, example at http://www.sics.se/contiki/wiki/index.p ... s_in_COOJA and the work-in-progress repo is at https://github.com/fros4943/cooja-avrora-patch-wip |
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Posted: Jun 22, 2012 - 10:06 PM |
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Joined: Apr 02, 2012
Posts: 46
Location: London
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Quote:
Start by writing simplest program to blink an LED. The only LED on the board is connected to 3290p, and I would not bother trying to work with it for start, so you'll probably have to connect an LED to one of GPIO pins.
So those tiny pinholes next to the 1284 and 3290 jtag headers are the GPIO pins? I've started reading the data sheets but the raven hardware sheet has a blurry representation of the GPIO pinouts... 3x10 pin minature holes? The jtag headers are already soldered and Ive succesfully connected the 1284 to the AVR dragon via a 10 pin ribbon cable and a very nice big to small adapter that was also in the box. The AVR studio read the 1284p succesfully. |
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Posted: Jun 22, 2012 - 10:15 PM |
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Joined: Apr 15, 2009
Posts: 4861
Location: San Jose, CA
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| I don't know for sure, but I would assume that they are GPIO, what else they could be? And they should be described somewhere. At least avr@atmel.com should have the schematics |
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The opinions and views expressed by me on this forum are my own and do not represent my employer or anyone else that I’m affiliated with.
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Posted: Jun 22, 2012 - 10:32 PM |
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Joined: Jun 15, 2008
Posts: 1756
Location: North Carolina USA
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| Those pinholes are landing pads, use #30 wirewrap wire and finish soldering before you visit the pub. The usart1 connections are a good first goal, with level shifters you can get debug prints. |
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