Cubietruck + PCM1794A. Anyone?

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Cubietruck + PCM1794A. Anyone?

Postby codewarrior » 04 Dec 2015, 16:10

Hello all,

I'm very new on this world of Cubietruck and Raspberry Pi boards development. I have a cubietruck board and I was wondering if is possible to implement on it the Texas Instruments PCM1794A DAC? Are the drivers available?

DAC: http://www.ti.com/product/pcm1794a

Cubietruck I2S specs: https://hifiduino.wordpress.com/2014/03 ... for-audio/
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Re: Cubietruck + PCM1794A. Anyone?

Postby hondagx35 » 04 Dec 2015, 17:09

Hi codewarrier,

the I2S drivers are installed and work.
You only have to make the hardware modifications from your link.

Frank
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Re: Cubietruck + PCM1794A. Anyone?

Postby codewarrior » 04 Dec 2015, 20:33

hondagx35 wrote:Hi codewarrier,

the I2S drivers are installed and work.
You only have to make the hardware modifications from your link.

Frank


Nice! I know there are DACs already made for the raspberry pi which has this PCM chip, for example,
- http://www.tjaekel.com/T-DAC/raspi.html
I can even adapt it to the CT by connecting the I2S pins properly, correct?
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Re: Cubietruck + PCM1794A. Anyone?

Postby codewarrior » 07 Dec 2015, 16:03

After doing some further investigations, the I2S bus clock of the CT can reach up to ~24MHz only which you can have a sample rates of 24/48 only. Is a bit disappointing. But I saw this, and wanted to ask also if RuneAudio has drivers for the XMOS chip which is a USB to I2S converter,

Asynchronous USB-to-I2S interface
http://luckit.biz/
Up to 384kHz
Up to 32-bit data

I think that using this USB interface along with a high end DAC is the way to go, instead of doing the modifications needed on the CT to use its slower I2S interface.

What you think?
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Re: Cubietruck + PCM1794A. Anyone?

Postby hondagx35 » 07 Dec 2015, 18:45

Hi,

the I2S bus clock of the CT can reach up to ~24MHz only which you can have a sample rates of 24/48 only.

Where did you find this?

From the A20 user manual digital audio section:
Two digital audio methods, one is I2S and the other is legacy PCM.
PCM supports 8 or 16bit sample rate 8~192kHz, I2S supports 8~24bit sample rate same as PCM.

Frank
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Re: Cubietruck + PCM1794A. Anyone?

Postby codewarrior » 07 Dec 2015, 19:37

hondagx35 wrote:Hi,

the I2S bus clock of the CT can reach up to ~24MHz only which you can have a sample rates of 24/48 only.

Where did you find this?

From the A20 user manual digital audio section:
Two digital audio methods, one is I2S and the other is legacy PCM.
PCM supports 8 or 16bit sample rate 8~192kHz, I2S supports 8~24bit sample rate same as PCM.

Frank


Well, sorry for the confusion. Correct, it supports up to 24/192. But is confusing when I read on the following link,

https://hifiduino.wordpress.com/2014/03 ... for-audio/

Theres a section that it mentions "Audio_PLL is the audio frequency clock derived from the 24MHz system clock. The PLL generates the 24.576 MHz and the 22.5792 MHz clocks. This means that the A20 is capable of bit-perfect playback for both the 44.1KHz and 48KHz family of sample rates."
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