topic Re: Watchdog timer does not work when power-down mode in LPC Microcontrollers

Watchdog timer does not work when power-down mode

enriquecerdeña — Wed, 06 Feb 2019 15:00:32 GMT

when I enter the power-down mode
Watchdog timer no longer works

Re: Watchdog timer does not work when power-down mode

ZhangJennie — Fri, 08 Feb 2019 14:12:29 GMT

HI Enrique Cerdeña

What's your chip part number?

Thanks,

Jun Zhang

Re: Watchdog timer does not work when power-down mode

enriquecerdeña — Fri, 08 Feb 2019 15:00:12 GMT

LPC802M001JDH16

Re: Watchdog timer does not work when power-down mode

ZhangJennie — Fri, 08 Feb 2019 15:58:01 GMT

Hi Enrique,

For LPC802, WWDT works in power down mode. How did you judge your WWDT not work?

Can you please test this:

1. the problem may be in low power setting.

Please check PCON_PM, make sure it is 2. if it's 3, MCU goes to Deep power down mode, this will disable WWDT.

2. the problem may be in WWDT setting, make sure you enabled watchdog power and clock ( check PDRUNCFG, SYSAHBCLKSTRL ).

set CLKOUTSEL to assign watchdog clock to an output pin. can you see the watchdog output clock with scope?

Have a nice day,

Jun Zhang

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Re: Watchdog timer does not work when power-down mode

enriquecerdeña — Thu, 14 Feb 2019 10:51:44 GMT

Good Morning!!! It worked!! thank you, but I still have problems, in the mode Deep power-down mode the consumption is 5 uA but in the power-down mode the consumption is 60 uA when I disconnect the sensor that is in GPIO 9 the consumption drops to 12 uA have any solutions to keep the 12uA ???

Re: Watchdog timer does not work when power-down mode

ZhangJennie — Thu, 14 Feb 2019 13:25:48 GMT

Hi Enrique!

Good to know your problem got solved.

Would you mind sharing the root cause?

You asked a different question under this thread. May I suggest you create a new thread for this new question? Let's keep "one thread one discussion topic". I really appreciate your understanding.

Have a nice day,

Jun Zhang

Re: Watchdog timer does not work when power-down mode

enriquecerdeña — Thu, 28 Feb 2019 12:14:00 GMT

HI Zhang Jennie!

The routine I developed using deep_power_down_mode is working but sometimes hangs !! with some tests I verified that after __WFI (); it returns to the next line and if it loses create a led to monitor !! what can be happening !!!!!

void low_power (void)
{

__WFI ();

while (1)
{
turnOnLed ();
delay_us (300000);
turnOffLed ();
delay_us (300000);

}//End while

}//End low_power

Re: Watchdog timer does not work when power-down mode

ZhangJennie — Mon, 04 Mar 2019 07:14:43 GMT

Hi Enrique,

In sleep mode, deep sleep mode, power down mode, program can get back to the place where it was entered low power mode once was awake.

BUT In Deep power down mode, During deep power-down mode, the contents of the SRAM and registers are not retained except for a small amount of data which can be stored in the general purpose registers of the PMU block. Thus program can't go back to the place where it went to sleep.

If the same problem is happened in sleep mode, deep sleep mode, power down mode, the possible reason is, for example:

- wake up by reset

- interrupt comes in once wake up

Have a great day,
Jun Zhang

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