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
VLCD is sourced from VCC when VLCDEXT = 0, VLCDx = 0, and VREFx = 0. VLCD is sourced from the internal charge pump when VLCDEXT = 0, VLCDCPEN = 1, and VLCDx > 0. The charge pump is always sourced from DVCC. The VLCDx bits provide a software selectable LCD voltage from 2.6 V to 3.44 V (typical) independent of DVCC. See the device-specific data sheet for specifications.
When the internal charge pump is used, a 4.7-µF or larger capacitor must be connected between the LCDCAP pin and ground. If no capacitor is connected and the charge pump is enabled, the LCDNOCAPIFG interrupt flag is set, and the charge pump is disabled to prevent damage to the device.
To reduce system noise the charge pump can be temporarily disabled. It is disabled when LCDCPEN = 0 and re-enabled when LCDCPEN is changed back to 1. If the charge pump is temporarily disabled the voltage stored on the external capacitor is used for the LCD voltages until the charge pump is re-enabled.
Some devices can also automatically disable the charge pump during certain periods of time (for example during an ADC conversion). To enable this feature set the corresponding LCDCPDISx bits in the LCDBCPCTL register. For details see the device-specific data sheet (if the feature is not listed in the data sheet it is not supported by the respective device).
NOTE
Capacitor Required For Internal Charge Pump
A 4.7-µF or larger capacitor must be connected from the LCDCAP pin to ground when the internal charge pump is enabled. If no capacitor is connected, the LCDNOCAPIFG interrupt flag is set and the charge pump is disabled.
The internal charge pump may use an external reference voltage when VLCDREFx = 01 (and LCDREXT = 0 and LCDEXTBIAS = 0). In this case, the charge pump voltage is set to a multiply of the external reference voltage according to the VLCDx bits setting.
When VLCDEXT = 1, VLCD is sourced externally from the LCDCAP, pin and the internal charge pump is disabled.