TM4C129XNCZAD: Internal RTC mode

Dear Charles,

Using hibernate example, I am able to generate Real Time Clock  from TM4C129XNCZAD  .

 I am using Hibernate mode (RTC Enabled)

We have also connected VBAT=3.0(Coin battery)  and as per datasheet nominal current consumption is 1.29 microAmpere@25degree celcius.

Following configuration 

SysCtlPeripheralEnable(SYSCTL_PERIPH_HIBERNATE);
HibernateEnableExpClk(ui32SysClock);
// Enable RTC mode.
HibernateRTCEnable();
// Configure the hibernate module counter to 24-hour calendar mode.
HibernateCounterMode(HIBERNATE_COUNTER_24HR);

It will maintain the calendar like external RTC?

Is any other or more configuration needed?

Rajesh Varma said:

 I am using Hibernate mode (RTC Enabled)

We have also connected VBAT=3.0(Coin battery)  and as per datasheet nominal current consumption is 1.29 microAmpere@25degree celcius.

Hi,

  Glad that you got it working very quickly. 

Rajesh Varma said:

It will maintain the calendar like external RTC?

Yes, the internal RTC has its own power domain supplied by the battery. It will maintain the calendar in hibernate mode. 

Rajesh Varma said:

Is any other or more configuration needed?

Not I'm aware of since you have it working if you follow the example.

Dear Charles,

Thanks for your reply.

As already said that I was connected 3.0 V Coin battery on VBAT Pin and measured the current in series with battery  in power- off mode 

it show 92.14 micro ampere and when switched on power on mode it show 1 microampere.

Why it is  taking  so much 92.14 micro ampere? 

Is any module off is required in code  so that it takes lesser current?

In datasheet Hibernate mode(RTC enabled )system Clock=OFF is written  what is that?

Please find our schematic also for refernce.

RTC_Battery2.pdf

Hi,

Rajesh Varma said:

it show 92.14 micro ampere and when switched on power on mode it show 1 microampere.

I suppose you meant to say you are measuring 92.14uA and you are expecting 1uA. Otherwise, It is not clear to me with your statement "and when switched on power on mode it show 1 microampere". 

  I have some doubt with your schematic. Please refer to the datasheet for hibernate mode using battery source. You leave the HIB open and therefore you are not disabling the power supplies to VDD. 

Dear Charles,

We only want to use RTC functionality of the Controller, is it possible?

As in our design we do not have any battery backup for our instrument, so that the instrument can gracefully enter in to Hibernation mode.

Basically our instrument is an Energy meter running on mains power supply. When Mains supply is present the device is ON and when no power only RTC section should be ON . For that we have connected 3.0V coin battery @VBAT pin.

As mention in you reply  we have not connected the HIB pin , as it is an out put pin which is generally connected to the Enable pin of the Regulator/Switch. In our design we are using LDO to convert 5.0 VDC to 3.3VDC to power up the controller. The LDO is not having any enable functionality.

You are requested to guide us further. As mentioned earlier when in power condition we had monitored current drawn around 90 µA from 3.0DV coin battery. 

Hi, 

 Please bear in mind that the current consumption given in the table is under the assumption that VDD and VDDA are both 0V. Why don't you remove VDD and VDDA and only keep VBAT and remeasure it again and what do you get?

Dear Charles,

As already mentioned that When mains AC supply is removed from our device and there is no other power backup for the instrument so directly

when mains supply is removed both VDD and VDDA  becomes Zero.

And 3.0 V DC coin battery is only connected to VBAT of the controller.

So i don't understand what you want to say?