Rockbox Player - Project to design and build a Free/Open hardware audio player

[casainho]

The developers for a port are the people who own the hardware, meaning you!

I understand. So I need to work on this idea and make It interesting for others developers buy the hardware and starting work on that.

Why not define an Open  Hardware Player and announce that developers of RB would support It, with propose that some hardware company make and sell it online? Can this be realistic or not?

[Bagder]

Why not define an Open  Hardware Player and announce that developers of RB would support It, with propose that some hardware company make and sell it online? Can this be realistic or not?

Feel free to do so. Rockbox is just a bunch of individuals with similar interests. We're all just separate persons that does what each one of us wants to do.

If this is realistic or not is up to the ones who think it is a good idea and the company they pitch the idea for. Perhaps the fact that there's no single such player today could be a hint that companies all over the world won't jump with joy when you approach them with this...

Personally, I would only be interested in this sub project if someone would build and sell me this player in a nice package, I won't buy anything that I need to put together myself since I am beyond worthless at such activities and I believe an mp3 player should be small and nice.

[casainho]

If this is realistic or not is up to the ones who think it is a good idea and the company they pitch the idea for. Perhaps the fact that there's no single such player today could be a hint that companies all over the world won't jump with joy when you approach them with this...

Personally, I would only be interested in this sub project if someone would build and sell me this player in a nice package, I won't buy anything that I need to put together myself since I am beyond worthless at such activities and I believe an mp3 player should be small and nice.

Bagder, thanks for sharing your thoughts.

As you, I think a mp3 player should be small and nice. Also I think that It should not have multimedia functions, for various reasons.

But, for someone build and sell to you  and others a player in a nice package, as you desire, and which is open hardware, I assume, we need to develop that hardware, invest our time and some money. We can see that big enterprises not desire to build an open hardware player. I think that there is money to win at selling this hardware! If we develop, make the project, some other company would just need to invest money, assembly It and sell It to recover invested money and get some profit. Am I dreaming?

 

[GodEater]

Am I dreaming?

The only way to find out is to stop talking about it and do it!

[casainho]

Am I dreaming?

The only way to find out is to stop talking about it and do it!

Do you know that I am doing that? and that implies looking for support here at RB. I need to feeling that I am not alone, because I can't do It alone, I can't port RB, nor design PCBS, nor I have experience for chose the microcontroler, nor DAC, nor USB chip, etc... But I can do some wiring, look at datasheets, buy a dev board and make some hacks in RB code.

[scharkalvin]

So, what's need more? We have microcontroler, SRAM, FLASH, USB, LCD, buttons. What about DAC?

Here's what's on the AVR32 cpu:
AVR32 based 32-bit MCU/DSP
Vectored multiplier co-processor, 32 KB on-chip SRAM, 16 KB instruction and 16 KB data caches, MMU, DMA controller. Peripherals include a 16-bit stereo audio DAC,2048x2048 pixel TFT/STN LCD controllers, 480 Mbps USB 2.0 with on chip transceivers (PHY) and, two 10/100 Ethernet MACs. Serial interfaces include RS232, USART, I2S, AC97, TWI/I2C, SPI, PS/2 and several synchronous serial modules (SSC) supporting most serial communication protocols.

So we have the DAC (only need a breakout connection and audio amp)

[casainho]

So, what's need more? We have microcontroler, SRAM, FLASH, USB, LCD, buttons. What about DAC?

Here's what's on the AVR32 cpu:
AVR32 based 32-bit MCU/DSP
Vectored multiplier co-processor, 32 KB on-chip SRAM, 16 KB instruction and 16 KB data caches, MMU, DMA controller. Peripherals include a 16-bit stereo audio DAC,2048x2048 pixel TFT/STN LCD controllers, 480 Mbps USB 2.0 with on chip transceivers (PHY) and, two 10/100 Ethernet MACs. Serial interfaces include RS232, USART, I2S, AC97, TWI/I2C, SPI, PS/2 and several synchronous serial modules (SSC) supporting most serial communication protocols.

So we have the DAC (only need a breakout connection and audio amp)

Good! :-) So in dev board we just need to solder wires for LCD, for headphones driver/amplifier and for buttons. $80 for dev board + $20 for nokia graphic LCD + $10 for the rest. It will not look good as an Ipod or a Sansa however It will be +-technically equal and total Free/Open hardware

I will put this information on Twiki page of RB. After I just need to find developers that can joint the project and buy their on dev boards e dev tools.

scharkalvin, do you want to participate? - I mean at buy also your tools.

[scharkalvin]

scharkalvin, do you want to participate? - I mean at buy also your tools.

Sounds interesting.  I'll probably lurk around on the forum and irc and jump in with both feet a bit latter.  I'll have some more 'mad money' available early next year.

BTW the Nokia LCD is a bitch to connect to as the connector is small and fragile.
You will need this as well http://www.sparkfun.com/commerce/product_info.php?products_id=600
which about doubles the cost.

Spark fun has a slightly cheaper LCD: http://www.sparkfun.com/commerce/product_info.php?products_id=8498
that uses a parallel interface (complete data available for the control chip on the website) that is a bit larger and only needs a few more wires to connect.
I can't tell from the photo or data sheet how hard this one would be to solder wires to or if a connector is available.

more info:
I looked at the schematic for the development board.  The D/A converter is a Delta-Sigma type and the output is raw data, not true analog.  So some external circuity is going to be needed to capture the audio.  Probably a latch, and some op-amps as an active low pass filter and pre-amp.  More research is needed to figure this out, (google).  There is also an AC97 interface, not sure what that is about (probably an i2c interface to external mixer / level control hw).  We'd need part of that for sw control of volume (would lose s/n ratio by adjusting volume by scaling d/a data).

Add schematic for d/a codeic interface from avr freaks.

[casainho]

Sounds interesting.  I'll probably lurk around on the forum and irc and jump in with both feet a bit latter.  I'll have some more 'mad money' available early next year.

Nice Could you add yourself to the list "People that are interested and can help"
http://www.rockbox.org/twiki/bin/view/Main/RockBoxPlayer

In the next weeks or so, we can work in advance before buy hardware, since we can read datasheets and have all information

About LCD, this: http://www.sparkfun.com/commerce/product_info.php?products_id=8498 , have 0,5mm pitch It's very difficult to solder, It's the same pitch as Nokia LCD and they wrote at Sparkfun:
Description: This is the itty-bitty connector for the Nokia color LCD. 10-Pins. Surface mount. Hard to find. 0.5mm pitch so be careful.

Can it be soldered by hand? Yes! Owen managed to solder wire wrap wire to the individual legs for testing - but then again, he's a magician. We can solder it well with a good PCB layout and easily with a stencil and hotplate.
http://www.sparkfun.com/commerce/product_info.php?products_id=570

So, no Nokia LCD and not this one, IMO.

About DAC, please don't laugh, but, what about 16 bit PWM + power drive? - yes, should be very low quality.

There are others projects Free/Open Source players that used DAC IC's, I will look at them. Did you look at that links in Twiki page?

[casainho]

About DAC:
The CODEC chip is a TLV320AIC23 from Texas Instruments. You could also use TLV320AIC23B since it's an exact equivalent. It is a 24-bit resolution Sigma-Dealta CODEC supporting up to 96 KHz sampling rate and comes with a built in headphone amplifier. The CODEC (coder-decoder) converts the digital samples produced by the DSP into an analog signal that can be fed to the headphones. It can also convert the analog signal connected to the line-in jack into digital signals and feed it to the DSP for processing.

The CODEC chip has a control port and a data port. The control port is linked to the DSP's SPI port whereas the data port is linked to the DSP's McBSP port. The DSP can control the CODEC configuration (e.g. volume, sampling rate, mute, etc). The data port is used to transfer digital audio samples to/from the CODEC.

We need the TSSOP-28 package for the DSPdap board. You can obtain it through TI sampling or Digikey.

I took that information from DSPdap: http://dspdap.sourceforge.net/hardware.html

Also I asked the responsible for that player, to join the idea of make a Free/Open hardware player for RB. Here the thread:
http://sourceforge.net/forum/forum.php?thread_id=1834813&forum_id=697896

[Llorean]

The same rules apply in New Ports as everywhere else folks: If nobody has responded, use the edit button. It's there for a reason.

[casainho]

The same rules apply in New Ports as everywhere else folks: If nobody has responded, use the edit button. It's there for a reason.

Sorry - I did not yet read the forum rules, I will. I am thinking in create a new tread just for this project.

[casainho]

Topic to discuss the Project to design and build a Free/Open hardware audio player for use with Rockbox.

Page of project on TWiki:
http://www.rockbox.org/twiki/bin/view/Main/RockBoxPlayer

Some forum topics with good info:
http://forums.rockbox.org/index.php?topic=6751.0

[scharkalvin]

Found another example of an open source player:

http://www.mikrocontroller.net/articles/ARM_MP3/AAC_Player

[casainho]

Found another example of an open source player:

http://www.mikrocontroller.net/articles/ARM_MP3/AAC_Player

I actualized the project page and I did add that link - nice, we have a lot to learn from others projects. That project is really near from this one, It just not have external SRAM, display and not designed with Rockbox in mind. I contacted the author and invited him to look/join this project.

I also put on list the DAC TLV320AIC23B and added the good points of her to list. This IC is used in ARM_MP3/AAC_Player and in the DSPdap projects. Are we ok with this DAC IC?

I had look for ARM9 development boards and I saw they are much more expensive that this one ATNGW100, which I found for $73 at mouser electronics or about $80 at Digikey! I am with a feeling that we should go for ARM9, however, looks like this AVR32 do more DMIPS than ARM9 and with less energy, also is cheap the dev board.

I had the idea of contact companies as Olimex (in future working version) asking for support at assembly and selling the player. Olimex build and sell MOD-MP3 MP3 PLAYER MODULE WITH VS1002 MP3 DECODER/ENCODER, they could do the same for this project - http://www.olimex.com/dev/mod-mp3.html
Also I will ask to the company where I work a possible price for 50 units.

At IRC some questions were asked, as If this player needs Real Time Clock or not, 32MB of SDRAM or not, etc... - I would like to redefine the minimum hardware for first version of the player. Can someone help? Thank you.