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On the PCA8551B LCD driver, after writing segment registers, segments transitioning to off turn off over 230ms then segments transitioning to on turn on over 230ms. I would expect these both to occur at the same time. Is this expected behavior?

Question asked by David Gardner on Nov 18, 2017
Latest reply on Nov 30, 2017 by David Gardner

See the attached video as a demonstration. As the digit on the far right transitions from 0 to 2, segments disable first and then the center segment enables afterwards.

 

This stuttered transition is aesthetically jarring. All segments change at the same time is preferable.

 

The LCD driver is configured to drive a static display, and the display has one backplane.

Device_ctrl = 0b00000100

Display_ctrl_1 = 0b00001101

Display_ctrl_2 = 0b00000000

 

Enabling a higher refresh rate or boost mode seems to have no effect.

 

The datasheet does not mention the timing of the segments transitioning when the segment registers are written, so it is unclear if this is expected behavior or not.

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