In the SAM L22 when a bit in the display memory is written to '1', the corresponding segment will be energized (ON / opaque), and de-energized (OFF / transparent) when this bit is written to '0'. The display memory stores the values of all segments to display. It is accessible through APB and should be filled before the next frame starts. A start of a new frame triggers copying the display memory into the shadow display memory. A display memory refresh is thus possible without affecting data already sent to the panel.
The display memory is not initialized at startup.
Each COM line has identical waveforms but different phases. For each phase of the frame according to the bit value in the shadow display memory the SEG lines are driven to VLCD and GND when the pixel is ON, or to one of the bias voltages when the pixel is OFF.
The COM and SEG signal waveform depends on the waveform mode being selected either Standard waveform mode or Low power waveform mode