MIKROE-798 mikroElektronika, MIKROE-798 Datasheet - Page 27

• Manufacturer Part Number: MIKROE-798
• Description: Development Boards & Kits - PIC / DSPIC EASYPIC v7 DEVELOPMENT SYSTEM
• Manufacturer: mikroElektronika

Specifications of MIKROE-798

• Rohs: yes
• Product: Development Boards
• Tool Is For Evaluation Of: PIC18F45K22
• Core: PIC
• Interface Type: RS-232, USB
• Operating Supply Voltage: 5 V
• Description/function: Development board only, touch screen, pencil, DS1820, LCD, serial cable, GLCD not included
• Dimensions: 266 mm x 220 mm

4 digit
7-seg display
One seven segment digit consist of 7+1
LEDs which are arranged in a specific
formation which can be used to represent
digits from 0 to 9 and even some letters.
One additional LED is used for marking
the decimal dot, in case you want to write
a decimal point in the desired segment.
EasyPIC
put together to form 4-digit 7-segment
display. Driving such a display is done
using multiplexing techniques. Data
lines are shared between segments, and
therefore the same segment LEDs in
each digit are connected in parallel. Each
digit has it’s unique digit select line,
™
v7 contains four of these digits
which is used to enable the digit
to which the data is currently being
sent. By multiplexing data through all
four segments fast enough, you create
an illusion that all four segments are in
operation simultaneously.
This is possible because human eye has
a slower reaction time than the mention
changes. This way you can represent
numbers in decimal or hexadecimal
form. Eight data lines that are common
for all the digits are connected to PORTD,
and digit select lines are connected to
RA0–RA3 lines on the microcontroller
sockets.
Figure 14-2: 4-digit 7-segment display schematic
DIS1
DIS0
R30
10K
R31
10K
COM1
COM0
Q2
BC846
Q1
BC846
Enabling the display
To enable digit select lines for the 4-digit
7-segment display you have to turn
on SW4.1, SW4.2, SW4.3 and SW4.4
switches. Digit select lines are connected
to RA0 – RA3 pins on the microcontroller
sockets, while data lines are connected to
RD0 – RD7 pins. Make sure to disconnect
other peripherals from the interface lines
in order not to interfere with signal/data
integrity.
DIS3
DIS2
R28
10K
R29
10K
COM3
COM2
Q4
BC846
Q3
BC846
DIS0
DIS1
DIS2
DIS3
SW4
RA0
RA1
RA2
RA3
Figure 14-1: Turn on switches
1 through 4 on SW4 to enable
4-digit 7-seg display
RD0
RD1
RD2
RD3
RD4
RD5
RD6
RD7
R81
R82
R83
R84
R85
R86
R87
R88
DATA BUS
470
470
470
470
470
470
470
470
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