24bit Right Justified I2S format help

Help and Support Help
1

Hi all,

Been using volumio for quite sometime.
I’m currently running Pi3 with Spdif (digi+), feed into my own DIY PCM63 DAC.

I built a 24bit discrete R2R DAC recently, and it sounds great using Spdif input.

I wish to make smaller 16bit / 20 bit or 24 bit R2R board specially for Raspberry pi and I need right justified format from GPIO / I2S out.

I googled online but only found a Japanese web page who provide a mod version of Volumio but that was ver 1.4 . it works though.

although I’m very in audio design ,I have zero coding knowledge. I wish someone can help me to add-in a right justified format ( preferably can select from 16 bit, 20 bit and 24 bit ) for Volumio 2 so that I can build discrete R2R DAC board specially for RPi.

thanks in advance.

2

Here’s my prototype which I’m connected to RPi with Spdif ( Digi+ ) I try to make it smaller and stack it on top of Rpi
R2R.jpg

3

Hello BigBulb,

I’m also trying to play music through a right justified 16bits DAC without any success !
did you find a way ?
Could you post the link you mentionned from japan ?

Thank you
Jean

4

Here’s the Japanese link: he mentioned its left justified though. don’t know how he modified the driver. horliy.seri.gr.jp/mt/horliy-blog … r-dac.html

5

If you have not as yet solved your isssues with converting i2s to 24 bit right justified, please find the link to Pacouk’s website, where he has implemented level shifting of the glue logic through hardware.

pavouk.org/hw/modulardac/en_pcm1704.html

I myself have implemented his designs for 20 bit and 18 bit right justified dacs; namely PCM63 and AD1865 and AD1860.

Alternatively, you may also find useful information on this at the following website and the schematic

tech.juaneda.com/en/projects/digitaldecoder.html

tech.juaneda.com/schema/ddecoder04.gif