LPC55S69 : Core1 and FLEXCOM2

[EugeneHiihtaja]

Hello !

Can I use I2C2 interface with speed 100/400kHz from Core1 when Core0 in PowerDown mode ?

I expect Core1 running at 1Mhz by using FRO_1MHZ clock and use FRO_1M or FROM_12M for clocking I2C interface.

Is this kind of configuration possible ?

Regards,

Eugene

[FelipeGarcia]

Hi Eugene,

Sorry for my late reply.

Please check the below statement from reference manual (chapter 13.2.3).

The power-down mode affects the entire system, the clock to all CPUs and peripheral is shut down and, if not configured, the peripherals in power domains PD_SYSTEM and PD_AO receive no internal clocks.

This means the I2C will be disabled from your entire system and the only way to left I2C running in power-down will be if you use Flexcomm3 as stated in reference manual (chapter 13.3.5).

GPIO group interrupts, selected serial peripherals in Flexcomm3 (SPI, I2C, USART), RTC, OS Event Timers and analog comparator can be left running.

Hope it helps!

Best regards,

Felipe

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[EugeneHiihtaja]

Hi Felipe !

Could you clarify dependencies between cores in case of power management.

Looks like cores are dependant and power management APIs can be called from Core0 only and wakeup sources affects both cores some how.

In make case I should RUN Core0 at 150Mhz for some short times and RTOS will put it to SleepMode sometimes and at known time to Power-down mode to conserve power.

Due Flexcomm 3 and few GPIO pins what are part of GINT0 , Core0 will wakeup sometimes to RUN mode from Power-Down mode.

Looks like it should work .

But what about Core1 behaviour while Core0 change power states ? Does it follow ?

I really expect that Core1 will be clocked by FRO1Mhz ( or FRO12Mhz) and can RUN or Sleep mode only.

It can poll some I2C interface sometimes and serve output of some individual pins.

But looks like it will be go to powerdown mode due Core0.

But it is written that Core1 can go to Sleep mode only.

So basically when I would like to run Core1 I should keep Core0 at list in Deep-sleep mode.

So all wakeup sources wakeup both Cores to RUN mode and I should put Core0 to Deep-Sleep asap and continue my operation on Core1 if need.

And if I need scheduled wakeup for Core1 and I can use RTC, OS event or other timers. What is recommended.

Core1 communicate to Core0 by using MAILBOX and it should always work becouse Core0 can't be in Powerdown if Core1 send interrupts.

Could you suggest what is the best power model in this case ?

How wakeup sources can wakeup both cores if GINT0 routed to Core0 and GINT1 to Core1 for example.

Regards,

Eugene

[FelipeGarcia]

Hi Eugene,

Some power modes affects both cores such power-down mode. This power mode shuts down clocks and peripherals for all CPUs just as the UM indicates. So if you want to send Core0 to power-down mode and Core1 to sleep or run mode will not be possible.

If you want to keep core1 in run mode you can use sleep mode in core0 as it only affects the relevant CPU.

Please refer to my colleague reply in this thread.

https://community.nxp.com/thread/516472#comment-1228975

Best regards,

Felipe

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