Atmel SAM4L Xplained Pro Evaluation Kit Atmel ATSAM4L-XPRO ATSAM4L-XPRO Data Sheet

42023E–SAM–07/2013

The shifting period is defined by the number of frame in TIM.FCx. The frame counter is selected
by writing its number in CSRCFG.FCS field. If frame rate is 50Hz (20ms) in standard waveform
mode, shifting period is 160ms up to 5.1s.

Initial value of circular shift register must be written in CSRCFG.DATA, the direction is defined
by CSRCFG.DIR bit (0 for left, 1 for right) and circular shift register operation is started by writing
a one to CR.CSTART.

Once enabled, data is shifted every TIM.FCx+1 frames, circular shift register is autonomous and
system can enter any sleep mode (only 32KHz must be running).

Figure 39-9. Wheel Animation Example (8 Segments)

LCDCA handles up to four ASCII characters tables, configured in Character Mapping Configura-
tion register (CMCFG). Instead of handling each segments in display memory for a selected
digit, user writes ASCII code in Character Mapping Control Register (CMCR) to display the cor-
responding character.

User can then drive several digits with few operations:

1.

select the Type of Digit (CMCFG.TDG), see 

,

2.

write the Start Segment value (CMCFG.STSEG) of the first digit,

3.

select Digit Reverse Mode (CMCFG.DREV) if required. If DREV is one, segment index 
is decremented,

4.

then write ASCII code in CMCR register.

If digit uses contiguous segments, repeat step 4 to update remaining digits. Segment index is
updated automatically according to the number of segment used in the digit and DREV value.

0

0

1

0

0

0

0

0

circular shift 

register

LCD wheel

b0

b1

b7

b6

b5

b4

b3

b2