Figure 43-14. 1/4 Bias, 1/8 Duty, Standard Waveform
Frame
V0
V1
V2
V3
COM0
COM1
COM2
...
COM6
COM7
SEG0
V0
V1
V2
V3
V0
V1
V2
V3
V0
V1
V2
V3
V0
V1
V2
V3
-V2
-V3
-V1
Frame
V0
V1
V2
V3
-V2
-V3
-V1
On
Off
V4
V4
V4
V4
V4
-V4
V4
-V4
Figure 43-15. 1/4 Bias, 1/8 Duty, Low-Power Waveform
Frame
V0
V1
V2
V3
COM0
COM1
COM2
…
COM6
COM7
SEG0
V0
V1
V2
V3
V0
V1
V2
V3
V0
V1
V2
V3
V0
V1
V2
V3
-V2
-V3
-V1
Frame
V0
V1
V2
V3
-V2
-V3
-V1
On
Off
V4
V4
V4
V4
V4
-V4
V4
-V4
Odd subframe
Even subframe
Odd subframe
Even subframe
43.6.1.5. LCD Frame Frequency
The LCD frame frequency is defined as the number of times the segments are energized per second. The
optimal frame frequency should be in range from 30Hz up to 100Hz to avoid flickering and ghosting
effect.
The 32KHz oscillator clock (CLK_SLCD_OSC) is the base clock to define the LCD frame frequency (or
frame rate) which in turn depends on the Duty Ratio bits in the Control A register (CTRLA.DUTY[2:0]).
CLK_SLCD_OSC is used to generate the LCD waveform data for the enabled phases.
CLK_SLCD_OSC is first divided by a prescaler PVAL=16..128, then divided by DIV=1..8: The prescaler
value PVAL is selected by writing the Prescaler bits in the Control A register (CTRLA.PRESC[1:0]), see
table below.
Table 43-3. Prescaler Selection
PRESC[1:0]
Prescaler Value (PVAL)
0x0
16
0x1
32
0x2
64
0x3
128
Atmel SAM L22G / L22J / L22N [DATASHEET]
Atmel-42402E-SAM L22G / L22J / L22N_Datasheet_Complete-07/2016
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