AN1048

Example of a quadruplex LCD with ST72F321B

13/21

Active time starts after the Output Compare 1 interrupt and dead time starts after the Output

Compare 2 interrupt. A total of 16 interrupts are generated in each frame period with four

interrupts per control period. There are 2 Output Compare 1 events (OC1_1 and OC1_2)

and 2 Output Compare 2 events in each phase.These are explained as follows:

segments which have to be turned OFF. The COM line which corresponds to this phase is

During OC2, all segments and COM lines are inactive (set to low level) if we want to

decrease the Vrms (see Figure 9) and COM lines are set low, segments are set high if we

want to increase the Vrms (see Figure 10).

During OC1_2, Segment Lines are supplied with voltage levels which are inverted to the one

applied during OC1_1.COM line which corresponds to this phase is set to high level.Other

Again during OC2, all segments and COM lines are inactive(set to low level) if we want to

decrease the Vrms and COM lines are set high, segments are set low if we want to increase

the Vrms (see Figure 10).