LPC1768 Internal RTC lag 4.5min/hr

[omkar787898]

I am using Internal RTC of LPC1768 but is lagging by 4 & half minutes for 1 hour. Is there any solution to make it accurate or this is the problem of LPC1768 internal RTC?

[Carlos_Mendoza]

Hi Omkar,

Which silicon revision is your MCU? Please notice that Revision A does not suffer from the RTC.1 erratum. The RTC oscillator is expected to work fine on rev A silicon.

Hope it helps!

Best Regards,
Carlos Mendoza
Technical Support Engineer

[omkar787898]

Hi,

Thanks for help but Where do i check the which revision i am using, Is

there anything mention on Controller chip?

Thanks & regards,

Omkar Teli.

On Tue, Feb 21, 2017 at 10:53 PM, Carlos_Mendoza <admin@community.nxp.com>

[Carlos_Mendoza]

Hi Omkar,

The LPC176x devices typically have the following top-side marking:

LPC176xxxx

xxxxxxx

xxYYWWR[x]

The last/second to last letter in the third line (field ‘R’) will identify the device revision.

Hope it helps!

Best Regards,
Carlos Mendoza
Technical Support Engineer

[omkar787898]

hi,

there is "LPC1768FBD100

SW1441.1

ZSD1219A"

so it is revision A?

Thanks & regards,

Omkar Teli.

On Thu, Feb 23, 2017 at 5:09 AM, Carlos_Mendoza <admin@community.nxp.com>

[Carlos_Mendoza]

Hi Omkar,

Yes, it is the Rev. A, this revision does not suffer from the RTC.1 erratum. The RTC oscillator is expected to work fine on rev A silicon. Which application are you suing? Have you tried the periph_rtc example that comes with LPCOpen?

LPCOpen Software for LPC17XX|NXP 

Best Regards!
Carlos Mendoza
Technical Support Engineer