topic Re: KL02 in VLPS/VLPW in Kinetis Microcontrollers

KL02 in VLPS/VLPW

nxa09603 — Sun, 09 Feb 2020 16:33:30 GMT

I have had problems trying to put a KL02 in VLPW or VLPS. I try the transition using a custom board (with only the IC placed, FEI).

I also tried using the Freedom KL02 board. In both cases the part stays in RUN mode.

Source code is the powe_manager example available in the SDK.

Any help is very welcome.

Thank you

Andre VB

Re: KL02 in VLPS/VLPW

mjbcswitzerland — Sun, 09 Feb 2020 17:57:04 GMT

Hi Andre

Try the binary for the FRDM-KL02Z at https://www.utasker.com/kinetis/FRDM-KL02Z.html, which includes low power control over its menu on the VCOM UART.
If it gives positive results you can simply use the open source uTasker project to do the same (which includes dynamic low power support for the KL02 and all possible clock configurations for custom boards - and simulation of the KL02 with Visual Studio).

Low power Kinetis videos at :
- https://www.youtube.com/watch?v=kWNlsAoMly4&list=PLWKlVb_MqDQFZAulrUywU30v869JBYi9Q&index=1
- https://www.youtube.com/watch?v=iZEMRiDmHzw&list=PLWKlVb_MqDQFZAulrUywU30v869JBYi9Q&index=5
- https://www.youtube.com/watch?v=v4UnfcDiaE4&list=PLWKlVb_MqDQFZAulrUywU30v869JBYi9Q&index=7

Regards

Mark
[uTasker project developer for Kinetis and i.MX RT]

Re: KL02 in VLPS/VLPW

Robin_Shen — Mon, 10 Feb 2020 02:09:27 GMT

Hi Andre,

External circuit connect to KL02Z chip may cause the extra current.

See Optimizing IO Power Consumption.

For the FRDM-KL02Z board, please try to remove the R16 first.(You can modify the codes in frdmkl02z_power_manager, select VLPS mode by codes instead of through UART)

If you don't want to modify the hardware, then before enter VLPS mode: you should reconfigure the UART pins to GPIO function, then configure the GPIO output voltage equal to external circuit.

Best Regards,

Robin

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

Re: KL02 in VLPS/VLPW

nxa09603 — Mon, 10 Feb 2020 12:21:01 GMT

Hi Mike

Never had used uTasker so far. Will try it know.

Thank you

Andre VB

Re: KL02 in VLPS/VLPW

nxa09603 — Mon, 10 Feb 2020 12:51:36 GMT

Hi Robin

Thanks for quick response. Please let me give a little bit more details. I did not measure the consumption in the FRDM board. Instead I have a custom board in which only the KL02 MCU is instantiated. Nothing else. I use the PEmicro Multilink ACP to debug through MCUxpresso semihost terminal.

I have also a custom code that calls a routine* to enter in VLPS from RUN. I wake up the part using LPTM. I notice the while{} loop stops when I call the VLPS routine but the consumption doesn't change. Approximately 3mA.

And I still got PRINTF messages in the semihost terminal. I tried to disconnect the debugger from the board. I still see 3mA.

Can the UART forcing the part not to enter in VLPS?

Thank you

Andre VB

SMC_PreEnterStopModes();
SMC_SetPowerModeVlps(SMC);
SMC_PostExitStopModes();

Re: KL02 in VLPS/VLPW

Robin_Shen — Tue, 11 Feb 2020 12:24:46 GMT

Please notice that debug will impact the low power test: Debug in low power modes.png Power mode transition triggers.png

So would you please try to disconnect the power and debugger, then power on KL02.

After modify the frdmkl02z_power_manager example, I think it can also test on your board. The FRDM-KL02Z board using external 32.768KHz crystal, you can modify BOARD_BootClockRUN select FEI mode by using clock tool.

modify BOARD_BootClockRUN.png