Backlight Control - Atmel SAM4E-EK User Manual

Figure 4-10. LCD block.
DNP
4.7k R14 LCD_DB0
8 1
LCD_DB4
7 2
LCD_DB2
RR1
6 3
LCD_DB3
DNP
5 4 LCD_DB1
4.7k
8 1
LCD_DB8
7 2
LCD_DB6
RR2
6 3
LCD_DB7
DNP
5 4
LCD_DB5
4.7k
DNP
LCD_DB9
4.7k R15
4.3.11.2

Backlight control

The LCD backlight is made of four integrated white chip-LEDs arranged in parallel. These are driven by an AAT3155
charge pump, MN15. The AAT3155 is controlled by PC13; the 0Ω resistor R24 is mounted in series on this line, which
permits to use it for other custom purposes. In that case, the pull-up resistor R20 maintains the charge pump
permanently enabled by default.
On the anode drive line, a 0Ω resistor R18 is implemented in series for an optional current limitation.
Figure 4-11. Backlight control.
PC13
+3V3
FB1
+3V3
PD[0..31]
PA[0..31] C32
C33
100nF
10uF
PC[0..31]
PC7
PC6
PC5
PC4
PC3
PC2
PC1
PC0
+3V3
PC11
PC8
R16
PC19
10K
PD18
JP8
NRST
LED_A R18
R17
4.7K
The part is placed as
close as possible to J4
NOT POPULATED
TVS, SOT23-5
+3V3
10
C35
R20
1uF
47K
R24
9
0R
11
5
BN03K314S300R
C38
4.7uF
4
C34
R13
100nF
47K
J3
FH26-39S-0.3SHW
1
VDD
2
LCD_DB17
DB17
3
LCD_DB16
DB16
4
LCD_DB15
DB15
5
LCD_DB14
DB14
6
LCD_DB13
DB13
7
LCD_DB12
DB12
8
LCD_DB11
DB11
9
LCD_DB10
DB10
10
LCD_DB9
DB9
11
LCD_DB8
DB8
12
LCD_DB7
DB7
13
LCD_DB6
DB6
14
LCD_DB5
DB5
LCD_DB4 15
DB4
16
LCD_DB3
DB3
17
LCD_DB2
DB2
18
LCD_DB1
DB1
19
LCD_DB0
DB0
20
VDD
21
RD
22
WR
23
RS
24
CS
25
NRST
RESET
26
IM0
27
IM1
28
GND
29
0R
LED-A
30
LED_K1
LEDK1
31
LED_K2
LEDK2
32
LED_K3
LEDK3
33
LED_K4
LEDK4
Y _UP 34
Y +
35
Y _DOWN
Y -
36
X_RIGHT
X+
37
X_LEFT
X-
38
NC
39
GND
D1
LCD
DNP
MN15
AAT3155ITP-T1
7
C1+ C2+
6
C1- C2-
EN/SET
8
OUTCP
IN
3
D1
2
D2
1
D3
12
GND D4
LCD BACKLIGHT
PIN 39
PINs
on
BOT
FTM280C34D
PIN 1
Six slots on PCB for LCD shield
C36
1uF
TP1
LED_A
LED_K1
C37
LED_K2
1uF
LED_K3
LED_K4
SAM4E-EK User Guide
42067B−SAM4E−04/2013
Z7
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