LPC51U68 Deep power down RTC

[Benoit2]

Hello all,

I try to wake up DPD from RTC wake up timer or RTC Alarm. All my test seems not working.
Have you an example with RTC wake up please?

--
1 :  I inspire from SDK example (but it with button)

2 : I configure with peripheral like this

NB : the timer is enable by software after initialize alarm and time.

3: I try adding the few code below :

 SYSCON_RTCOSCCTRL_EN(1);

  SYSCON_STARTER_RTC(1);

  RTC_EnableWakeUpTimerInterruptFromDPD(RTC,1);

  RTC_EnableAlarmTimerInterruptFromDPD(RTC,1);

I call like this :

      RTC_SetWakeupCount(RTC_PERIPHERAL, RTC_WAKE_UP_TIME);

      POWER_EnterDeepPowerDown(0);

      // or like this

      //POWER_EnterDeepPowerDown(SYSCON_PDRUNCFG_PDEN_SRAMX_MASK | SYSCON_PDRUNCFG_PDEN_SRAM0_MASK);

4 : I understand that Wakeupcount is onetime use.that why I reinit it before enter DPD

5 : the RTC_IRQHAndler work with wakeup or alarm before I call EnterDeepPowerDown.

thanks for help.

Benoit

[xiangjun_rong]

Hi,

For the deep-power-down function, I suppose that you have to add the line:

SYSCON->STARTERSET[0] |= SYSCON_STARTER_RTC_MASK;

BTW, pls follow up the deep power down waking-up procedure, I copied from UM11071.pdf, the deep-power down follows up Reset procedure rather than interrupt after waking-up:

7.3.5 Deep power-down mode
In deep power-down mode, power and clocks are shut off to the entire chip with the
exception of the RTC.
During deep power-down mode, the contents of the SRAM and registers (other than those
in the RTC) are not retained. All functional pins are tri-stated in deep power-down mode
as long as chip power supplied externally.
7.3.5.1 Power configuration in deep power-down mode
Deep power-down mode has no configuration options. All clocks, the core, and all
peripherals are powered down. Only the RTC is powered, as long as power is supplied to
the device.
7.3.5.2 Wake-up from deep power-down mode:
Wake-up from deep power-down can be accomplished via the reset pin or the RTC.
7.3.5.3 Programming deep power-down mode using the RTC for wake-up:
The following steps must be performed to enter deep power-down mode when using the
RTC for waking up:
1. Set up the RTC high resolution timer. Write to the RTC VAL register. This starts the
high res timer if enabled. Another option is to use the 1 Hz alarm timer.
2. Call the power API function, see Chapter 8 “LPC51U68 Power profiles/Power control
API”.
7.3.5.4 Wake-up from deep power-down mode using the RTC:
The part goes through the entire reset process when the RTC times out:
• The PMU will turn on the on-chip voltage regulator. When the core voltage reaches
the power-on-reset (POR) trip point, a system reset will be triggered and the chip
boots.
• All registers will be in their reset state.

Pls have a try.

BR

XiangJun Rong

[Benoit2 · Accepted solution]

Hello XiangJun Rong,

thanks for helping.
The problem was hardware. I don't know why.

for informations :
my last settings are :

and to go to DPD:

RTC_EnableWakeUpTimerInterruptFromDPD(RTC,1);
RTC_SetWakeupCount(RTC, 6000);
POWER_EnterDeepPowerDown(0);

I don't need to do this :

SYSCON->STARTERSET[0] |= SYSCON_STARTER_RTC_MASK;
according datasheet "Deep power-down mode has no configuration options"

Many thanks for help.

kind regards,
Benoit