with codec is the master, playing dsd64 has some noise

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hushange
Member++
Posts: 30
Joined: Tue Oct 11, 2016 7:08 am

with codec is the master, playing dsd64 has some noise

Postby hushange » Thu May 04, 2017 4:44 am

Hi xmos:

i have a board which baseed on skc-su1 with 6.15.2 firmware.
we have make some difference, our xmos is the slave, codec is the master.
pcm file can playing well from 44khz to 384khz.
but when playing dsd64 dsd128 dsd256 dsd512, there is some noise.
the noise is obvious on dsd64, and will become smaller and smaller on dsd128 dsd256 dsd512, the noise is minmum on dsd512.
i have attached the noise wave.

1. whether there is someone has the same problem as me ?
2. whether the noise comes from xmos ? how to remove it?

many thanks
[url=https://postimg.org/image/4av79vvmb/][img]
hushange
Member++
Posts: 30
Joined: Tue Oct 11, 2016 7:08 am

Postby hushange » Thu May 04, 2017 4:47 am

noise jpg is attached!

my changes on xmos code:

switch (divide)
{
case 4:
asm volatile("out res[%0], %1"::"r"(p_dsd_dac[0]),"r"(dsdSample_l));
asm volatile("out res[%0], %1"::"r"(p_dsd_dac[1]),"r"(dsdSample_r));
#ifndef CODEC_MASTER
p_dsd_clk <: 0xCCCCCCCC;
p_dsd_clk <: 0xCCCCCCCC;
p_dsd_clk <: 0xCCCCCCCC;
p_dsd_clk <: 0xCCCCCCCC;
#endif
break;

case 2:
asm volatile("out res[%0], %1"::"r"(p_dsd_dac[0]),"r"(dsdSample_l));
asm volatile("out res[%0], %1"::"r"(p_dsd_dac[1]),"r"(dsdSample_r));
#ifndef CODEC_MASTER
p_dsd_clk <: 0xAAAAAAAA;
p_dsd_clk <: 0xAAAAAAAA;
#endif
break;

default:
/* Do some clocks anyway - this will stop us interrupting decouple too much */
asm volatile("out res[%0], %1"::"r"(p_dsd_dac[0]),"r"(dsdSample_l));
asm volatile("out res[%0], %1"::"r"(p_dsd_dac[1]),"r"(dsdSample_r));
#ifndef CODEC_MASTER
p_dsd_clk <: 0xF0F0F0F0;
p_dsd_clk <: 0xF0F0F0F0;
p_dsd_clk <: 0xF0F0F0F0;
p_dsd_clk <: 0xF0F0F0F0;
p_dsd_clk <: 0xF0F0F0F0;
p_dsd_clk <: 0xF0F0F0F0;
p_dsd_clk <: 0xF0F0F0F0;
p_dsd_clk <: 0xF0F0F0F0;
#endif
break;
}
Attachments
dsd64_noise.jpg
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dsd64_noise.jpg
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