Brief
Below is architecture of what I want to go. In this section, components in red rectangle are implemented.
I already have TAS5518 8 channel full digital amplifier, it can accept direct 4 way I2S.
I want to be free from "jitter" debating.
- There should be only 1 clock source, neighbor to amplifier.
- I2S distance should be some inches.
- No SPDIF or AES/EBU
I bought Xylo-L, USB2.0 and Xilinx FPGA board from www.fpga4fun.com.
11.2896MHz crystal was added to supply master clock.
04/01/2008
testing Xylo-L. 44.1kHz x 4bytes x
8channel = 1.411MB/sec, I hope Xylo-L can
do this.
I modified attached "bidirectional" sample.
Test
VHDL for Xylo-L
Test
C++ code for PC
Result.
So far... maybe Xylo-L can be used for, at least,
44.1k/16bit/Stereo 4Way output device.
2MB/sec throughput is ( 512Bytes / operation) / (0.25ms /
operation).
0.25msec = 2 x 125 usec / HighSpeed USB microframe.
a small unhappy of Xylo-L are here,
- It has Document written in English
but there are no firmware source code, and schematic. Documentation is
always detour.
- I can not change EndPoint configuration to
Isochronous, or more longer.
04/05/2008
Still testing Xylo-L. It looks like these problem or limitation on spec
exist.
- when USB-FX2 FIFO is fully filled, it goes to
STALL state.
- Loopbacking (read how many bytes are
transfered) can solve.
- Xylo-L works only 12/24/48 MHz FIFO clock.
VHDL should be separated 12MHz area / 11.2896MHz area.
These source can do continuous 705,600Bytes/sec (for
44.1kHz/16bit/4Way) communication.
Test
VHDL(2) for Xylo-L
Test C++(2) code for PC
But I can't think now it can process more data, like 88.2k/24bit/4way
(2116.8KB/sec).
My final aim is to play LINN Studio Master format. a
little bit shortage of speed....
04/11/2008
I2S
Distribution VHDL
WaveX
Player Code CPP
This dirty VHDL was generated from Excel. Lazy for thinking.
Now testing with simple I2S receiver board made before.
04/13/2008
I connected to TAS-4i.Dirty shake up.
But sound is "No Excuse", Real 8192 TAPs FIRed 4Way.
Compared with IIR 24dB/Oct, more "Flat" "Clean" and live. It sounds
like when I changed my glasses.
4/14/2008
I ordered Athlon BE/2GB/320GB/400W Zen
Fanless/GeForce9600GT/Xp 64bit, to get headroom for additional
HDD, PCI FPGA board, one more 9600GT etc.
it was not so expensive than FanLess small PC..
04/15/2008
newegg
is great, so quick.
Fanless PC parts arrived, now installing. Both CPU, VGA cooler is very
huge.
I will install everything..
04/20/2008
PC is working so so stable.
But terrible thing: I found Cypress does not providing xp64 driver.
Xp32 will be re-installed...
04/25/2008
Temparature of CPU: no problem.
Temparature of VGA: you need to clock-down to 450MHz or so. then no
problem.
Temparature of Motherboard: pretty high on north and
south bridge. go to BIOS to down clock the bus speed.
Temparature of HDD: no problem.
Noise from HDD: HDD works only at copying wavex file to memory, no
problem.
http://www.quietpcusa.com/Smart-Drive-HDD-Silencer-2002C-P211C0.aspx
Next if in the mood??
Another way of data transfer. USB is most weak chain of this system.
return to home
