PSoC 6 ECO Source Maximum Frequency?

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MotooTanaka
Level 9
Level 9
Distributor - Marubun (Japan)
First comment on blog Beta tester First comment on KBA

Dear Cypress,

One of my customer has been developing their product using PSoC 6 (CY8C6136BZI-F14).

Their product will use both USB and I2S and they want to run CM4 as fast as possible.

To support Audio frequency of 48kHz and 44.1kHz, they are planning to feed 34.4064MHz to ECO.

They will generate 147.456MHz clock using PLL and for the USB clock they are planning to feed 48MHz to External Clock.

But when I tested with PSoC Creator, the maximum frequency I could feed to ECO was 33.3MHz.

Meantime in the data sheet the maximum frequency of ECO source is stated as 35MHz.

The customer also confirmed this using MTB 2.2.

But to stay in the safer side, they want to confirm/ask the following questions.

Question 1.

Can the customer feed 34.4064MHz as the source of ECO?

Or is/are there limitation that ECO can accept only up to 33.3MHz?

Question 2.

How much diffusion between I2S clock and USB Audio is allowed?

Can it be in the order of 0.1% or 0.01%?

Best Regards,

28-Oct-2020

Motoo Tanaka

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1 Solution
RodolfoGL
Employee
Employee
250 solutions authored 250 sign-ins 5 comments on KBA

Question 1)

Yes, you can use 34.4064 MHz.

Previously, we mistakenly stated 33.33 MHz. We have characterized and confirm we can run up to 35 MHz, as stated in the datasheet. PSoC Creator does not reflect that yet. But you can use the PDL to set ECO frequency with PSoC Creator.

Question 2)

The USB requires 0.25% clock accuracy. The I2S does not require any, but it is recommend to drive the audio subsystem from PLL.

There are many techniques to sync the USB and I2S clocks. This code example implements one:

GitHub - cypresssemiconductorco/mtb-example-psoc6-usb-audio-device-freertos: This example demonstrat...

If you don't sync the I2S and USB clocks, doesn't matter how accurate they are, you eventually would see some artifacts.

View solution in original post

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2 Replies
RodolfoGL
Employee
Employee
250 solutions authored 250 sign-ins 5 comments on KBA

Question 1)

Yes, you can use 34.4064 MHz.

Previously, we mistakenly stated 33.33 MHz. We have characterized and confirm we can run up to 35 MHz, as stated in the datasheet. PSoC Creator does not reflect that yet. But you can use the PDL to set ECO frequency with PSoC Creator.

Question 2)

The USB requires 0.25% clock accuracy. The I2S does not require any, but it is recommend to drive the audio subsystem from PLL.

There are many techniques to sync the USB and I2S clocks. This code example implements one:

GitHub - cypresssemiconductorco/mtb-example-psoc6-usb-audio-device-freertos: This example demonstrat...

If you don't sync the I2S and USB clocks, doesn't matter how accurate they are, you eventually would see some artifacts.

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MotooTanaka
Level 9
Level 9
Distributor - Marubun (Japan)
First comment on blog Beta tester First comment on KBA

Dear RodolfoG-san,

Thank you very much for your very fast answer!

Best Regards,

28-Oct-2020

Motoo Tanaka

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