Lcd Main Features - ST STM32L4x6 Reference Manual

RM0351
22.2

LCD main features

• Highly flexible frame rate control.
•
Supports Static, 1/2, 1/3, 1/4 and 1/8 duty.
• Supports Static, 1/2, 1/3 and 1/4 bias.
•
Double buffered memory allows data in LCD_RAM registers to be updated at any time
by the application firmware without affecting the integrity of the data displayed.
–
•
Software selectable LCD output voltage (contrast) from V
•
No need for external analog components:
–
–
–
–
–
• The contrast can be adjusted using two different methods:
–
–
•
Full support of low-power modes: the LCD controller can be displayed in Sleep, Low-
power run, Low-power sleep and Stop modes or can be fully disabled to reduce power
consumption.
•
Built in phase inversion for reduced power consumption and EMI (electromagnetic
interference).
•
Start of frame interrupt to synchronize the software when updating the LCD data RAM.
•
Blink capability:
–
–
•
Used LCD segment and common pins should be configured as GPIO alternate
functions and unused segment and common pins can be used for general purpose I/O
or for another peripheral alternate function.
Note: When the LCD relies on the internal step-up converter, the VLCD pin should be connected
to V with a capacitor. Its typical value is 1 µF (see C
SS
for further information).
LCD data RAM of up to 16 x 32-bit registers which contain pixel information
(active/inactive)
A step-up converter is embedded to generate an internal V
V
DD
Software selection between external and internal V
an external source, the internal boost circuit is disabled to reduce power
consumption
A resistive network is embedded to generate intermediate V
The structure of the resistive network is configurable by software to adapt the
power consumption to match the capacitive charge required by the LCD panel
Integrated voltage output buffers for higher LCD driving capability.
When using the internal step-up converter, the software can adjust V
V and V
LCDmin LCDmax
Programmable dead time (up to 8 phase periods) between frames.
Up to 1, 2, 3, 4, 8 or all pixels which can be programmed to blink at a configurable
frequency
Software adjustable blink frequency to achieve around 0.5 Hz, 1 Hz, 2 Hz or 4 Hz.
DocID024597 Rev 3
Liquid crystal display controller (LCD)
.
to V
LCDmin LCDmax
voltage higher than
LCD
voltage source. In case of
LCD
voltages
LCD
value in the product datasheets
EXT
.
between
LCD
659/1693
690