SLAS797C August 2014 – August 2018 MSP430FR6927 , MSP430FR69271 , MSP430FR6928 , MSP430FR6977 , MSP430FR6979 , MSP430FR69791
PRODUCTION DATA.
LCD segment (Sx) and common (COMx) signal traces are continuously switching while the LCD is enabled and should, therefore, be kept away from sensitive analog signals such as ADC inputs to prevent any noise coupling. TI recommends keeping the LCD signal traces on one side of the PCB grouped together in a bus-like fashion. A ground plane underneath the LCD traces and guard traces employed alongside the LCD traces can provide shielding.
If the internal charge pump of the LCD module is used, the externally provided capacitor on the LCDCAP pin should be located as close as possible to the MCU. The capacitor should be connected to the device using a short and direct trace and also have a solid connection to the ground plane that is supplying the VSS pins of the MCU.
For an example layout of connecting a 4-mux LCD with 40 segments to an MSP430FR6989 and using the charge pump feature, see the Water Meter Reference Design for Two LC Sensors, Using Extended Scan Interface (ESI).