LCD & RTC interference

[lpcware]

Content originally posted in LPCWare by Atieh on Thu Dec 25 09:50:53 MST 2014
I designed a LPC4357 based 4 layer board. A 32KHZ crystal is connected to RTCX1 and RTCX2 pins with 10pF capacitors.
The board layers are : top(signal) - mid1(power) - internal plane(GND) - bottom(signal).
Internal RTC was working fine till LCD initialise was added to code. Due to LCD, RTC has lag or works fast. How can I eliminate this problem?

Regards

[lpcware]

Content originally posted in LPCWare by h.lotfi on Sat Dec 27 08:02:06 MST 2014
Hi,
i had this problem with LPC1788, after examination i found out this problem is for GND...
my RTC GND was weak...
i made a new PCB with good GND near RTC capasitors and solve my problem, and my other advise is solder RTC Xtal to GND.

Good luck