Atmel SAM4L Xplained Pro Evaluation Kit Atmel ATSAM4L-XPRO ATSAM4L-XPRO Data Sheet
Product codes
ATSAM4L-XPRO
1039
42023E–SAM–07/2013
ATSAM4L8/L4/L2
The Clock Division field (CLKDIV) in TIM register defines the division ratio in the clock divider.
This gives extra flexibility in frame rate setting.
This gives extra flexibility in frame rate setting.
Where:
N = prescaler divider (8 or 16).
K = 8 for 1/4, 1/2 and static duty.
K = 6 for 1/3 duty.
WMOD = 0 in low power waveform mode, = 1 in standard waveform mode.
K = 8 for 1/4, 1/2 and static duty.
K = 6 for 1/3 duty.
WMOD = 0 in low power waveform mode, = 1 in standard waveform mode.
Note that when using 1/3 duty, the frame rate is increased by 33% compared to the values listed
above and in low power waveform mode, the frame rate is divided by two.
above and in low power waveform mode, the frame rate is divided by two.
39.6.5.2
Frame Counters
For several functions (blinking, automated modes,...) a frame counter is used to create a time
base. There are three independent frame counters (FC0, FC1 and FC2) which can be associ-
ated to any function (refer to corresponding section).
base. There are three independent frame counters (FC0, FC1 and FC2) which can be associ-
ated to any function (refer to corresponding section).
For FC0 only, the prescaler of 8 can be bypassed by writting a one to TIM.FC0PB.
Note that frame counter frequency depends on frame duration therefore of waveform mode.
Table 39-4.
LCD Clock Divider (1/4 Duty, WMOD=1)
CLKDIV[2:0]
Divided
by
Frame rate (1/4 Duty)
F(CLK_LCD) = 32 kHz
F(CLK_LCD) = 32768 Hz
N=8
N=16
N=8
N=16
0 0 0
1
500 Hz
250 Hz
512 Hz
256 Hz
0 0 1
2
250 Hz
125 Hz
256 Hz
128 Hz
0 1 0
3
166.667 Hz
83.333 Hz
170.667 Hz
85.333 Hz
0 1 1
4
125 Hz
62.5 Hz
128 Hz
64 Hz
1 0 0
5
100 Hz
50 Hz
102.4 Hz
51.2 Hz
1 0 1
6
83.333 Hz
41.667 Hz
85.333 Hz
42.667 Hz
1 1 0
7
71.429 Hz
35.714 Hz
73.143 Hz
36.671 Hz
1 1 1
8
62.5 Hz
31.25 Hz
64 Hz
32 Hz
Table 39-5.
Frame Rate Examples (WMOD=1)
CLK_LCD
Duty
K
PRESC
N
CLKDIV[2:0]
Frame rate
32.768 kHz
Static
8
1
16
4
32768 / (8*16*(1+4)) = 51.2 Hz
32.768 kHz
1/2
8
1
16
4
32768 / (8*16*(1+4)) = 51.2 Hz
32.768 kHz
1/3
6
1
16
4
32768 / (6*16*(1+4)) = 68.267 Hz
32.768 kHz
1/4
8
1
16
4
32768 / (8*16*(1+4)) = 51.2 Hz
FrameRate
F CLK_LCD
(
)
K
N
1
CLKDIV
+
(
)
×
×
2
1
WMOD
–
(
)
×
(
)
----------------------------------------------------------------------------------------------------
=
f
FCx
FrameRate
TIM.FCx
8
×
(
) 1
+
-----------------------------------------------
=