SLAU367P October 2012 – April 2020 MSP430FR5041 , MSP430FR5043 , MSP430FR50431 , MSP430FR5847 , MSP430FR58471 , MSP430FR5848 , MSP430FR5849 , MSP430FR5857 , MSP430FR5858 , MSP430FR5859 , MSP430FR5867 , MSP430FR58671 , MSP430FR5868 , MSP430FR5869 , MSP430FR5870 , MSP430FR5872 , MSP430FR58721 , MSP430FR5887 , MSP430FR5888 , MSP430FR5889 , MSP430FR58891 , MSP430FR5922 , MSP430FR59221 , MSP430FR5947 , MSP430FR59471 , MSP430FR5948 , MSP430FR5949 , MSP430FR5957 , MSP430FR5958 , MSP430FR5959 , MSP430FR5962 , MSP430FR5964 , MSP430FR5967 , MSP430FR5968 , MSP430FR5969 , MSP430FR5969-SP , MSP430FR59691 , MSP430FR5970 , MSP430FR5972 , MSP430FR59721 , MSP430FR5986 , MSP430FR5987 , MSP430FR5988 , MSP430FR5989 , MSP430FR5989-EP , MSP430FR59891 , MSP430FR5992 , MSP430FR5994 , MSP430FR59941 , MSP430FR6005 , MSP430FR6007 , MSP430FR6035 , MSP430FR6037 , MSP430FR60371 , MSP430FR6041 , MSP430FR6043 , MSP430FR60431 , MSP430FR6045 , MSP430FR6047 , MSP430FR60471 , MSP430FR6820 , MSP430FR6822 , MSP430FR68221 , MSP430FR6870 , MSP430FR6872 , MSP430FR68721 , MSP430FR6877 , MSP430FR6879 , MSP430FR68791 , MSP430FR6887 , MSP430FR6888 , MSP430FR6889 , MSP430FR68891 , MSP430FR6920 , MSP430FR6922 , MSP430FR69221 , MSP430FR6927 , MSP430FR69271 , MSP430FR6928 , MSP430FR6970 , MSP430FR6972 , MSP430FR69721 , MSP430FR6977 , MSP430FR6979 , MSP430FR69791 , MSP430FR6987 , MSP430FR6988 , MSP430FR6989 , MSP430FR69891
The LCD_C controller uses the fLCD signal from the integrated clock divider to generate the timing for common and segment lines. With the LCDSSEL bit, ACLK with a frequency between 30 kHz and 40 kHz or VLOCLK can be selected as clock source into the divider. The fLCD frequency is selected with the LCDPREx and LCDDIVx bits. The resulting fLCD frequency is calculated by:
The proper fLCD frequency depends on the LCD's requirement for framing frequency and the LCD multiplex rate. It is calculated by:
fLCD = 2 × mux × fFrame
For example, to calculate fLCD for a 3-mux LCD with a frame frequency of 30 Hz to 100 Hz:
fFrame (from LCD data sheet) = 30 Hz to 100 Hz
fLCD = 2 × 3 × fFrame
fLCD(min) = 180 Hz
fLCD(max) = 600 Hz
With fACLK/VLOCLK = 32768 Hz, LCDPREx = 011, and LCDDIVx = 10101:
fLCD = 32768 Hz / ((21+1) × 23) = 32768 Hz / 176 = 186 Hz
With LCDPREx = 001 and LCDDIVx = 11011:
fLCD = 32768 Hz / ((27+1) × 21) = 32768 Hz / 56 = 585 Hz
The lowest frequency has the lowest current consumption. The highest frequency has the least flicker.