Linux/AM3352: Enabling SSC

Sung-IL

Mastermind 30810 points

Part Number: AM3352

Tool/software: Linux

Dear Champs,

Could you please let me know how SSC can be enabled in AM3352 Linux SDK v4.0?

When I checked below e2e, the most appropriate place to enable SSC is uboot and board file in Linux SDK v4.0, right?

<u-boot_dir>/board/ti/am335x/board.c.

Is it ok to set bit CM_CLKMODE_DPLL_xxx.DPLL_SSC_EN?

or should other parameters like Modulation frequency(fm) be programmed also?

Thanks and Best Regards,

SI.

over 7 years ago

0 Biser Gatchev-XID over 7 years ago

TI__Guru**** 393215 points

Hi,

See section 8.1.6.6 of the AM335x TRM Rev. P. Note that Spread spectrum clock is only supported for the LCD and MPU PLLs on this device, as stated in the Note at the end of this section.

0 Sung-IL over 7 years ago in reply to Biser Gatchev-XID

TI__Mastermind 30810 points

Hi Biser,

I already checked section 8.1.6.6 of the AM335x TRM and I questioned about SW modification. Could you please let me know how SW should be modified? Is it OK only to set bit CM_CLKMODE_DPLL_xxx.DPLL_SSC_EN in board file of UBOOT?

Thanks and Best Regards,
SI.

0 Pavel Botev over 7 years ago in reply to Sung-IL

TI__Guru**** 170625 points

Sung,

Setting only DPLL_SSC_EN bit is not enough. PSDK4 has ready function that you can use - set_mpu_spreadspectrum()

u-boot-2017.01/arch/arm/mach-omap2/am33xx/clock_am33xx.c

patchwork.ozlabs.org/.../

See also:

e2e.ti.com/.../842912
e2e.ti.com/.../198104

Regards,
Pavel

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Linux/AM3352: Enabling SSC