SAM4L Datasheet, PDF (1043/1185 Pages) ATMEL Corporation – ATSAM ARM-based Flash MCU

ATSAM4L4/L2
Note that when using external V _LCD, the fine contrast controlled by CFG.FCST is inoperative.
Table 39-11. LCD Power Supply Pins
SR.EN CFG.XBIAS
VLCD
BIASH
BIASL
CAPH / CAPL
0
x
H.Z.
H.Z.
H.Z.
H.Z.
0
V_LCD
2/3 V_LCD
(also in static
mode)
1/3 V_LCD
(also in static mode)
Capacitor
Pump Charge
1
1
Input for
VLCD
- Input for BIASH
- H.Z. if static
bias
- Input for BIASL
- H.Z. if static bias
H.Z.
Figure 39-11. LCD Power Supply Block Diagram
BANDGAP
Reference
Pump
Contrast
x3
x2
x1
XBIAS
CAPH
CAPL
VLCD
BIAS2
BIAS1
COMy
SEGx
Figure 39-12. Internal and External Bias Generation
Internal Generation
(static or 1/3 Bias)
External Generation
(static)
Device
VCC
VCC
Device
VCC
VCC
CAPH
CAPL
(1)
100 nF
VLCD
BIASH
BIASL
GND
100 nF
(1)
100 nF
(1)
100 nF
(1)
CAPH
CAPL
VLCD
BIASH
BIASL
GND
Ext. VLCD
External Generation (example)
(1/3 Bias)
Device
VCC
VCC
CAPH
CAPL
VLCD
BIASH
BIASL
GND
(2)
Ext. VLCD
(1) Values are given for design guidance only.
(2) Bias generation can be provided by other voltage source than a divison resistor
42023C–SAM–02/2013
1043