Liquid Crystal Displays
or
LCDs
are cheap and
popular way of representing information to the
end user of some electronic device. Character
LCDs can be used to represent standard and
custom characters in the predefined number of
fields. EasyPIC
™
v7 provides the connector and the
necessary interface for supporting
2x16 character
LCDs
in 4-bit mode. This type of display has two rows
consisted of 16 character fields. Each field is a 7x5 pixel
matrix. Communication with the display module is done
through
CN7
display connector. Board is fitted with uniquely
designed plastic display distancer, which allows the LCD module
to perfectly and firmly fit into place.
GND and VCC
- Display power supply lines
Vo
- LCD contrast level from potentiometer P4
RS
- Register Select Signal line
E
- Display Enable line
R/W
- Determines whether display is in Read or Write mode. It’s
always connected to GND, leaving the display in Write mode all
the time.
D0–D3
- Display is supported in 4-bit data mode, so lower half of
the data byte interface is connected to GND.
D4–D7
- Upper half of the data byte
LED+
- Connection with the backlight LED anode
LED-
- Connection with the backlight LED cathode
We have allowed LCD backlight to be enabled in two different ways:
1. It can be
turned on with full brightness
using
SW4.6
switch.
2. Brightness level can be determined
with PWM signal
from the
microcontroller, allowing you to write custom backlight controling
software. This backlight mode is enabled with
SW4.5
switch.
LCD 2x16 characters
GND
GND GND GND GND
GND
VCC-5V
VEE
RB0
RB0
RB1
RB1
RB2
RB2
RB3
RB3
LCD-GLCD BCK
K-LCD
RB5
RB5
RB4
RB4
VCC-MCU
P4
10K
VCC-MCU
LCD-GLCD BPWM
R10
1K
R89
Q11
BC846
4K7
56
R93
CN7
LCD2X16
Vss Vdd Vee RS R/W
E
D0 D1 D2
D3 D4 D5
D6 D7
A
K
RC2
VCC-5V
ON
SW4
DATA BUS
Figure 11-1: On-board LCD 2x16 display connector
Figure 11-2: 2x16 LCD
connection schematics
Standard and PWM-driven backlight
Connector pinout explained
Make sure to turn off the power supply before placing LCD onto
the board. Otherwise your display can be permanently damaged.
In order to use PWM backlight both
SW4.5
and
SW4.6
switches must be
enabled at the same time.
IMPORTANT:
IMPORTANT:
page 24
displa
ys
