QUERY about MCLK clock drive on WM8898/ES8838 for Audio
Posted: Fri Apr 24, 2020 2:20 pm
Hi Vonger
We are a product design business in the UK. I have been familairising with VOCORE2 which we've bought from you, for a new project.
It's working beautifully - congratulations on a great product.
I have a question about Audio. Note, I have VoCore2, not Dock, so I don't have your sample: but I've looked at your Schematics.
I see you used WM8898 / ES8838 in the original Dock, and so I guess the drivers are in the current image.
My question is about the hardware design you used -- and the source of MCLK you used for the audio device (Master clock).
I think, if I am reading schematics right, you used GPIO0 originally to feed this ? I am guessing you were able to route a clock out of the CPU via GPIO to drive the ES8388 ?
But - on the later 'Dock20' Schematic, I see you drive MCLK, from a local crystal oscillator.
I am designing a project with audio now, using VoCore2, and I need to add WM8898 / ES8838 to my interface. I want to follow your best advice for the device -- would you recommend a local oscillator to drive MCLK, and if so, what frequency do you use ? I have seen both 384x fs and 256x fs as options.
(Could you also please explain, what the 'GPIO drive' to MCLK was).
I presume fs = 48Khz ? so a Crystal oscillator clock, needs to be either 12.288MHz or 18.432MHz I think. Can you confirm what you use on the Dock now ?
Many thanks for your help - much appreciated -- we hope to place a volume order with you soon.
With best regards
Mike H, London UK
We are a product design business in the UK. I have been familairising with VOCORE2 which we've bought from you, for a new project.
It's working beautifully - congratulations on a great product.
I have a question about Audio. Note, I have VoCore2, not Dock, so I don't have your sample: but I've looked at your Schematics.
I see you used WM8898 / ES8838 in the original Dock, and so I guess the drivers are in the current image.
My question is about the hardware design you used -- and the source of MCLK you used for the audio device (Master clock).
I think, if I am reading schematics right, you used GPIO0 originally to feed this ? I am guessing you were able to route a clock out of the CPU via GPIO to drive the ES8388 ?
But - on the later 'Dock20' Schematic, I see you drive MCLK, from a local crystal oscillator.
I am designing a project with audio now, using VoCore2, and I need to add WM8898 / ES8838 to my interface. I want to follow your best advice for the device -- would you recommend a local oscillator to drive MCLK, and if so, what frequency do you use ? I have seen both 384x fs and 256x fs as options.
(Could you also please explain, what the 'GPIO drive' to MCLK was).
I presume fs = 48Khz ? so a Crystal oscillator clock, needs to be either 12.288MHz or 18.432MHz I think. Can you confirm what you use on the Dock now ?
Many thanks for your help - much appreciated -- we hope to place a volume order with you soon.
With best regards
Mike H, London UK