Untrimmed IMO frequency accuracy of PSoC3

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NaMo_1534561
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Hello,

Until the IMO setting is completed in ClockSetup(), the frequency of the IMO is not adjusted by Trim.

The oscillation accuracy of IMO after Trim can be confirmed with the data sheet specifications (± 2% @ 3MHz).

What is the oscillation accuracy of IMO before Trim?

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Morimoto-san,

Most are in few percent. But it is not trimmed and not guaranteed by design. According to Page-8 in AN60631, the IMO’s frequency range from maximum to minimum trim is approximately -33%/+25%. I think it can assume this value as absolute range for IMO before trimmed.

Best Regards,

Ryan

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RyanZhao
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Morimoto-san,

You mentioned IMO will trim after ClockSetup(), may I know where you get this info from?

Best Regards,

Ryan

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NaMo_1534561
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Hello Ryan-san,

I refer below application notes and also Register TRM.

AN60616 PSoC3 and PSoC 5LP Startup Procedure

https://www.cypress.com/file/141051/download

AN60631 PSoC3 and PSoC 5LP Clocking Resources

https://www.cypress.com/file/140916/download

Best Regards,

Naoaki Morimoto

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Morimoto-san,

We don't have spec of IMO before trimmed.

However, as described in AN60616,

Once reset is released, the hardware-controlled portion of startup begins. Hardware startup(reset and boot).

Although the main IMO output is used during part of the reset phase, it is not trimmed until the boot phase.

After Hardware startup completed, Firmware Startup(Mainly is CyFitter_cfg.c executing which has ClockSetup() included in) will be executed.

That means before Firmware Startup(before CyFitter_cfg.c executed), IMO has been the trimmed accuracy.

Best Regards,

Ryan

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NaMo_1534561
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Distributor - Macnica (Japan)
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Hello Ryan-san,

OK, I tell the customer that we don't have the non-trim IMO specs.

As a reference, what percentage of IMO accuracy is assumed before trimming?

Is it a few percent or tens of percent?

Best Regards,

Naoaki Morimoto

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Morimoto-san,

Most are in few percent. But it is not trimmed and not guaranteed by design. According to Page-8 in AN60631, the IMO’s frequency range from maximum to minimum trim is approximately -33%/+25%. I think it can assume this value as absolute range for IMO before trimmed.

Best Regards,

Ryan

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NaMo_1534561
Level 5
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Distributor - Macnica (Japan)
100 replies posted 100 sign-ins 50 replies posted

Hello Ryan-san,

Thank you for your answer.

I appreciate giving the undocumented information. Please close this query.

Best Regards,

Naoaki Morimoto

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