A FPGA Audio System in raspberrypi size and open source later.

[antercreeper]

Still some works are not done and need to fix. Will be opensourced after finishing these.

[antercreeper]

Welcome for any suggestions.
Q&A:
1. Why not DDR?
A: because you need to pay for those analog things if you flows ASICs.(only SRAMs, standard cells, normal IOs and PLLs.) This FPGA is ready for validations before making ASICs.
2.

[antercreeper]

Right up corner is for Bluetooth module, nRF5340 + CSR8811, support both Bluetooth classic and LE Audio(espressif doesn't support LE audio, and dual band bluetooth.).
It takes much money(about $10 for 1 pcs), and i am sure I will populate only once and never again :'(

[antercreeper]

Old version, those mistakes have been fixed in the new version.

[xvr]

Seems to me it will be quite costly for DIY niche 

[antercreeper]

reasons? for example

6 layers at JLCPCB i cost about $42 and get about 7 pics.
The XC7K70T-FBG484 cost me $22, the biggest part of course.
The most expensive(for me) part for me is MAX9850 from ADI(Analog Inc. 's(include Maxim) parts are always of high performance and very expensive), about $3.
the FT2232H from FTDI. and the 256Mbits HyperRAM.
Si5351 replaced to MS5351, at same performance and lower price.(In fact I choose 5P49V6965 before, but too expensive and doesn't provide too much improvement)

the other things are quite cheap. 1 dollar or less. 1 dollar, 1 dollar, 1 dollar...
for example MP2122 1pcs at $0.14, TPS62480 1pcs at about $0.7. SOIC-8 150mil slot(just the FRAM/EEPROM in the diagram, you can replace it from the slot)(from LOTES) is a bit expensive, but bellow or about $1.
of course you can unpopulate some of them.

In fact the biggest tough thing for me is how to solder the big BGA FPGA to the board......

[xvr]

> The XC7K70T-FBG484 cost me $22, the biggest part of course.

Not so bad, I'd expect more expensive 

> 6 layers at PCBWAY i cost about $42 and get about 7 pics.

$6 per single PCB. Could be cheaper.

> n fact the biggest tough thing for me is how to solder the big BGA FPGA to the board......

Yes, PCBA could be expensive, especially in singles quantities.

So I'm still very interested in final price (for single piece and for small batch, say 100 pcs).

If it will be less than $100 per piece (in small batch) it will be wonderful 

[antercreeper]

Maybe
But i am not interested in doing some kickstar. 
I think open sourcing is enough, and you can modify these, replace some ICs to reduce cost, or reroute the whole crappy lines.(The first time for me, so it is not very perfect, and some traces are ugly.)

[xvr]

Unfortunately, open source is not enough. BGA chip is a quite hard to solder at home - it requires special equipment and experience. But PCBA in single quantities is a VERY expencive.

[antercreeper]

I am about to try use a heating table below and a heat gun(maybe I should replant the solder ball to Pb ones for lower temperature requirement). And you will hear good or bad news soon . The manual from TI introduced this way.
However, the experience in China is just go to look for some computer repair shops and let them sold these big BGA chips with BGA rework stations. for about $8.29 1 pcs :'(

[langwadt]

The XC7K70T-FBG484 cost me $22, the biggest part of course.

must have fallen of a truck somewhere, I think a regular distributor wants close to 10x that ...

[dietert1]

This FPGA may have 1000 times the computing power you need for an audio application. Can you write some sentences about the application and how you arrived at using a FPGA for this? What is the large memory meant for? Is this a MP3 player? Is this for machine learning?
Many years ago i made a special digital crossover for active speakers using a Spartan3 50K FPGA. Some years later i found the same could be implemented on an Arm Cortex 3. At the time a Kinetis K22. Cortex architecture includes a very nice DSP instruction set and at clock rates of 120 MHz you have about 1200 cycles per (stereo) audio sample if your audio stream is 96 KHz sampled. This was enough to implement two 4-ways time-correct crossovers.

Regards, Dieter

[xvr]

> However, the experience in China is just go to look for some computer repair shops and let them sold these big BGA chips with BGA rework stations. for about $8.29 1 pcs :'(

Yes, in China it could be easy. But for the rest of the world it is very tricky. Here PE magazine says that some PCB requires expert to assemble it, just because some SMD of 0805 size was used

[SiliconWizard]

The XC7K70T-FBG484 cost me $22, the biggest part of course.

must have fallen of a truck somewhere, I think a regular distributor wants close to 10x that ...

Yeah. While prices from Digikey and the like are not representative of the real price you can get in quantities, $22 looks pretty fishy. Possibly the price they get in China, but I personally wouldn't know which chinese distributor to get these from at this price. It's probably possible though as there are Kintex 7 dev boards from China for about $80.

[antercreeper]

160t would be 2x price. maybe just because 70t is more common.(only common device is cheaper.  :'()

[antercreeper]

 
In fact i just solder 0402s by hands.
But for QFN and BGAs, you don't know if there are soldered properly. Factorys use x ray inspection machine.

[antercreeper]

Just4Fun
In fact it is just a platform includes all you need to design and do verifications for any audio things. Of course you can make one AI core, or AI voice synthesizer. https://bellard.org/tsac/ or LPCnet from Xiph.org. and then things will go from 1000% to 0%.
By now I implemented the whole FLAC codec(A cpu core+LPC core) and used 20% resources.
running at 50MHz.

[antercreeper]

all is done!
However some plastic melted......

[asmi]

How are you planning to cool this part? It will cook itself in no time once you place any load onto it.

[antercreeper]

The FPGA? Maybe u can stuck a heat sink with some tape on it. It's my fault, haven't design holes for mounting heat sinks(no spare space).
It depends on your design. 
For mine, almost no heat generated, about 20~30mA @1 volt VCCINT, as cool as the ambient. The hottest part is the FTDI FT2232 and MS5351M Clock, at about 40~45 degrees celsius.
And in the second version, I connect the thermal signal to the FPGA reset pin(you can use it in your design), and can stuck your design if it overheated.

[asmi]

For mine, almost no heat generated, about 20~30mA @1 volt VCCINT, as cool as the ambient.

What your design does? That seems way too low even for unprogrammed device.

And in the second version, I connect the thermal signal to the FPGA reset pin(you can use it in your design), and can stuck your design if it overheated.

There are no "thermal signals" in FPGA. It's got internal ADC with die temperature sensor connected to one of it's channels, so you don't need any external connections, but you DO need to implement it in your design and do something about it.

[antercreeper]

Sorry for my bad English  :'(

I use TMP435 to monitor the diode of the FPGA and 1. trigger reset of your design while too hot 85 degrees 2. cut the Power while overheated, maybe 100 degrees.

[antercreeper]

The current is too small for 8millohms shunt resistors(and the solder can also add some resistors). i am sure just millamps, and I can't measure it very well.
for thermal camera, it is as cold as the ambient...
tips: max is 6 amps, 6*8=48millvolts