The selected frame counter defines the number of frames before the SLCD triggers a new DMA block
transfer. For example, if frame rate is 50Hz (20ms) in standard waveform mode, the characters string can
be displayed with a period from 160ms up to 5.1s.
Figure 43-27. Sequential Character String Example (NDIG=5, frame rate=50Hz, FC0.OVF=31)
H E
L
W O R
T H
I
String = ’HELLOWORLDTHIS IS AUTOMATED ’
L
L
S
O
D
I
S
A U T O M
A T
E
D
0
5.1
10.2
15.3
20.4
25.5
t (s)
Scrolling of Characters String
This mode displays characters of a string on a digits chain on the LCD panel with a scrolling effect. For
each step, a part of the characters string is displayed by shifting the string by one character in left
direction. The period between each step can be configured on frame counter basis. This mode requires
an internal frame counter (time base) and the DMA controller to transfer the character string.
To use this mode, character mapping must be configured first (see
configuration must be done to specify the scrolling display. In the Automated Character Mapping
Configuration register (ACMCFG):
•
Write the size of the digits chain on the LCD panel to the Number of Digit bits (ACMCFG.NDIG).
•
Write the number of scrolling steps to the Steps bits (ACMCFG.STEPS).
The number of steps is equal to string length - NDIG + 1.
•
Write a '1' to the Mode bit in order to to select the scrolling mode (ACMCFG.MODE).
•
Configure a frame counter to set the display period (period between two steps, see
) and write the frame counter index to the Frame Counter Selection bits (ACMCFG.FCS).
The DMA controller should be configured to transfer several times the same block corresponding to the
complete characters string (the string may require some blank characters at the end in order to be
Atmel SAM L22G / L22J / L22N [DATASHEET]
Atmel-42402E-SAM L22G / L22J / L22N_Datasheet_Complete-07/2016
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