Opensource hardware CDJ/MIDIPC - Raspberry Pi ($25)

[ReggieUK]

There's the broadcom chip that is as open as it can be, with only the gpu being closed and for good reason, their security stuff is all on there, so all the codec enabling options, e-fuses etc. reside there, it deals with booting, bearing in mind that this chip is also in commercial products, you can understand why they would want to protect that investment and that of their oem buyers.


If it'll definitely work, I'll give it a go, thanks :-)

[MrPopinjay]

The driver and the chip are not the same thing! You could have an open source driver with a closed source chip and visa versa

[ReggieUK]

Yeah but you're getting down to splitting hairs now, the majority of people have zero need to know about the inside of the chip, the chip doesn't on it's own define the whole of what the raspberry pi is, otherwise we could call a roku a raspberry pi. And they did provide an api for the gpu iirc. Then again, I don't know of any other mainstream embedded processors that have released the source code for their GPU? And no one in their right mind would expect any graphics chip company to release the schematics for their chips, it would be commercial suicide.

I'm sure we could go on like this for another couple of pages but it's all besides the point, mixxx will work :-D Let's agree to differ and call it something else?

[MrPopinjay]

That's it! Open source computers more or less don't exist, and I doubt they will during my lifetime. The nearest you get is the lemote yeeloong, RMS' computer of choice, which I believe has completely open source firmware and drivers. But even then, the hardware itself is closed source. On the other hand much simpler open source hardware is doing well in the 3D printing scene! We live in exciting times.

So what are you planning to make? A controller with embedded mixing software? Sounds exciting!

[ReggieUK]

This afternoon I've built a midifighter classic on a breadboard, just a single button to confirm my atmega32u2 chip (pin/code compatible with the at90usb162) really is firing on all pins. I got the stock firmware on the chip and it seemed to be communicating with the utility over the weekend, had to wait until today for the 74hc165 chips to turn up. Still waiting on the tlc5928 led driver chips and the mcp3004 4 channel ADC chips for the expansion port.

After that I'm not entirely sure, there's a platform called 'midibox' that revolves around lpc1769 chip that looks interesting, it's modular using an rtos based firmware, I had hoped to plug a midifighter into that but no usb host on the midibox platform and no midi out on the midifighter all it would take though would be midi out on the fighter via serial. I'd hoped to introduce a midi sequencer engine between the midifighter and a host machine, dial in your tempo, setup some patterns, like effects etc., then trigger the patterns using the midifighter.

the raspberry pi could be used as a simple cheap portable mixing platform, you could even add your own fighter style interface using 8 gpio, then I guess it could be entirely possible to do the same as above in software.

Then again, I'm more inclined to use something like a mini2440/mini210s board or anything that can do usb gadget that you can compile your own kernel for, they'll have a load more gpio, they'll act as a straight usb to midi to usb to midi bridge, add a 3.5-9" lcd with touchscreen or use composite out on the 2440/6410 or hdmi out on the 210 and you've got a very powerful relatively open source platform to design what you like.

I've got a couple of other ideas but they really can wait for now, I need those other chips to turn up so I can hopefully confirm something :-)

[MrPopinjay]

That. Sounds. Awesome!

[ReggieUK]

I can't be the first person to think of this, I'm not necessarily thinking of writing much code myself, I'm looking for open source/free solutions :-) It feels like anything I'm thinking of doing has probably already been done, I'm not exactly new to midi/midicontrollers but I'm sure I've missed out on a lot of technological advances.

I've found some information for switching the pi serial port into something that can spit out 31250, although I'm not sure that's entirely necessary, also found a lightweight midi sequencer/looper, gives me lots and lots of options :-)

I've also now added some simple code to output serial on the midifighter, not tested yet.

It should work on official midifighter classic hardware but not sure how code compatible it would be, at the very least it will probably break the digital input on the expansion port, so it would need an official update to fix it I think.

It's easy enough to make the changes for the development board I'm using, it's got all the pins broken out so I can just reassign the digital expansion in 2 to one of the unused pins which would leave PD3 (txd1) free for midi output.