Attempting to connect C6713DSK to (2) PCM4204EVM’s ADC’s and (1) PCM4104EVM DACs. Eight channel of input, 8 channels of output.
Using McASP1 (I2S Format) as master to generate clocks and outputs to DACs, McASP0 is configured as slave with inputs from ADC’s.
LRCLK = 48kHz = Sample Frequency (Fs) = (actual measurement 48.8kHz)
BCLK = 3.072MHz = Fs * 64 (actual measurement = 3.125MHz = 48.8kHz * 64)
HCLK = 12.288MHz = Fs * 256 = (estimated actual = 12492.8)
PCM4204 switch settings:
SW1
FS0 LO
FS1 LO
FS2 LO
S/M HI
FMT0 HI
FMT1 LO
FMT2 LO
HPFD LO
SUB LO
/DSDTEST HI
SW3
MONO34 LO
MONO12 LO
FMT1 LO
FMT0 LO
CLK0 LO
CLK1 LO
/DIT LO
SW5
OSC1 LO
OSC2 LO
/EXT HI
PCM4104 switch settings:
SW1
MODE = LO
MUTE = LO
DEM0 = HI
DEM1 = LO
FMT0 = HI
FMT1 = LO
FMT2 = LO
FS0 = LO
FS1 = LO
SW3
/ASP = LO
TDM = LO
I have previously connected the C6713DSK to a homemade board with PCM1802 ADC’s and PCM1728 DAC’s. Even with 24” long sloppily wired clocks and data lines, this works fine, just a little noise on the analog inputs that I want to eliminate by going to PCM4104s and PCM4204s. Plus the PCM1728 is out of production so I’ll have to change that regardless.
I can hear a little bit of the actual audio signal under the very loud noise that I believe is caused by poor quality clocking signals. I have shortened the clocks and data lines to 18” with little improvement.
From PCM4204 data sheet, page
For Left Justified, Right
Justified, and I2S data formats, the BCK rate is typically
128fS in Single Rate sampling mode, and 64fS in Dual or
Quad Rate sampling modes. Although other BCK clock
rates are possible, they are not recommended due to the
potential for clock phase sensitivity issues, which may
degrade the dynamic performance of the PCM4204.
If I understand this correctly, since Fs = 48kHz, I should use Single Rate sample mode, and the BCLK should be 128 * Fs. How does this work when (32-bit Word * 2 channels = 64 bit length). Are you saying that there would be 64 BCLKs for the 32 bit Left channel data, then 64 BCLKs for the 32 bit Right channel data.
I have also noticed that there is a newer “high reliability” version of the PCM4104. If I change the current chips on the PCM4104EVM’s to the “high reliability” version, will this improve my situation?
Any help would be greatly appreciated.
Thanks
Jim Andrew
