LCD_C Operation
941
SLAU367P – October 2012 – Revised April 2020
Copyright © 2012–2020, Texas Instruments Incorporated
LCD_C Controller
NOTE:
LCDSx Bits Do Not Affect Dedicated LCD Segment Pins
The LCDSx bits only affect pins with multiplexed LCD segment functions and digital I/O
functions. Dedicated LCD segment pins are not affected by the LCDSx bits.
36.2.7 LCD Interrupts
The LCD_C module has four interrupt sources available, each with independent enables and flags.
The four interrupt flags, namely LCDFRMIFG, LCDBLKOFFIFG, LCDBLKONIFG, and LCDNOCAPIFG,
are prioritized and combined to source a single interrupt vector. The interrupt vector register LCDCIV is
used to determine which flag requested an interrupt.
The highest priority enabled interrupt generates a number in the LCDCIV register (see register
description). This number can be evaluated or added to the program counter to automatically enter the
appropriate software routine. Disabled LCD interrupts do not affect the LCDCIV value.
Any read access of the LCDCIV register automatically resets the highest pending interrupt flag. If another
interrupt flag is set, another interrupt is immediately generated after servicing the initial interrupt. A write
access to the LCDCIV register automatically resets all pending interrupt flags. In addition, all flags can be
cleared by software.
The LCDNOCAPIFG indicates that no capacitor is present at the LCDCAP pin when the charge pump is
enabled. Setting the LCDNOCAPIE bit enables the interrupt.
The LCDBLKONIFG bit is set on the rising edge of BLKCLK when the LCD switches to blinking status if
blinking is enabled with LCDBLKMODx = 01 or 10. The LCDBLKONIFG bit is also set on the edge of
BLKCLK when the blinking memory is selected as the display memory with LCDBLKMODx = 11. The bit is
automatically cleared when an LCD or blinking memory register is written. Set the LCDBLKONIE bit to 1 to
enable the interrupt.
The LCDBLKOFFIFG bit is set at the falling edge of BLKCLK when the LCD switches to nonblinking status
if blinking is enabled with LCDBLKMODx = 01 or 10. The LCDBLKOFFIFG bit is also set at the edge of
BLKCLK when the LCD memory is selected as the display memory with LCDBLKMODx = 11. The bit is
automatically cleared when an LCD or blinking memory register is written. Set the LCDBLKOFFIE bit to 1
to enable the interrupt.
The LCDFRMIFG is set at a frame boundary. It is automatically cleared when a LCD or blinking memory
register is written. Setting the LCDFRMIFGIE bit enables the interrupt.