Entering low power mode at MPC5633M

[pavelhavlik]

Hi

I'd like to ask two questions about low power modes at MPC5633M.

According to "MPC5634M Microcontroller Reference Manual" I set SIU_HLT and execute 'wait' instruction.

First I set SIU_HLT of all modules and wait until SIU_HLTACK is set and than set SIU_HLT[CPUSTP] and execute wait.

Program gets stopped and if external interrupt comes, wait instruction exits. Problem is that power

consumption of the core running at 1.2V is very high during the wait. (cca. 25mA @1.2V)

In halt(stop?) mode shall be clocks into core gated so I don't know why it is so.

Does anybody have any explanation or hints how it works and how shall be the MCU put properly into halt mode?

Secondly I'd like to understand the relation of HID0[NAP|SLEEP|DOZE] flags to the SIU_HLT register. For now

I belive that these flags are just information flags going out of the core when MSR[WE] is set for the SoC to

know that user wants to enter some low power mode. Thay have nothing to do with real core low-power mode transition.

Is my understaning right?

Thank you in advance for any advices and explantions

[lukaszadrapa · Accepted solution]

Hi,

unfortunately this device is not suitable for low power applications. The typical current consumption in stop mode is about 25mA. As per datasheet, IDDSTOP is max 50mA. So, your observation is about right.

NAP/SLEEP/DOZE modes are not implemented, so the flags in HID0 have no effect.

Lukas

[pavelhavlik]

Hi Lukas

Thanks for the reply and explanantion.

Hardware guys will no be happy to hear it:-)

We are new to the powerPC processors, do know/think that there could be a pin-compatible replacement of our MPC5633M, that would support some low-power mode? Maybe MPC564xA? We seem to be a little lost in all the derivatives.

Thank you

Pavel

[lukaszadrapa]

Hi Pavel,

sorry for delay, I was out of office.

Yes, MPC564xA is pin compatible but the current consumption in low power mode is relatively high too. There are no other pin compatible devices.

I'm afraid that redesign will be necessary if you need to get lower currents. I don't know your requirements, so I can't suggest the best derivative but always check the datasheet for more information about the current consumption.

Regards,

Lukas

[pavelhavlik]

Lukas,

Thank you very much.

Regards

Pavel