S12Z Cpu TRIM

[axhubner]

Hi,

I have some questions regarding trimming the internal oscillator.

- Is it necessary to trim the internal oscillator? In the datasheet is written that the CPU is factory trimmed.

- In production we perform a mass erase before programming. Does the mass erase also erases the factory trimmed value?

- Where is the trim value located in the global memory map?

- For production we are using Flashrunner. I know, PE-Micro in combination with Codewarrior, automatically trims the CPU while downloading. Do you know if trimming is also supported by Flashrunner?

- Is there an Application Note for Trimming the S12Z Processor?

Thanks Axel

[RadekS]

Ho Axel,

1. In most of the cases, IRC1M (1MHz) is not necessary to trimming. It is already trimmed from the factory. If you need some specific trimming due any specifically required clock value, package encapsulation,… the trimming may be simply changed by write into IRCTRIM register (after every reset). A factory trim value for 1MHz is loaded from Flash Memory into the IRCTRIM register after reset, which can be overwritten by the application if required.
2. No, the mass erase do not affect factory data.
3. The factory trim values are stored in P-Flash IFR (0x1F_C000 – 0x1F_C0FF), however the exact address and format is not specified.
4. Unfortunately, I don’t have experience with Flashrunner tool, please contact PEmicro for these details: http://www.pemicro.com/SRS/main_screen_user.cfm
5. I am not aware of any Application note for trimming IRC1M oscillator. I may offer to you the example code for trimming ACLK oscillator (20kHz low accuracy oscillator for low power modes) on the base of the bus clock.

I hope it helps you.

Have a great day,
RadekS

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