Showing posts with label Projects. Show all posts

P10(1R) Dot Matrix Display Interfacing With Arduino

The dot matrix display that I have is P10(1R),

Don’t worry about the upper section being empty, I later did program it to show text


Actual display Board	Back Part [ PCB ]

It is P10(1R)-DP4 536-V5 Type

The closest datasheet that I got for this is http://www.hlec.com.cn/userfiles/files/20120928014657.pdf

These Large Display Boards have multiple Units cascaded together. I call each unit a Panel

So Multiple Panels being chained together make a large display board

Here is how my board and it panels are chained to form the large display

The Blue colored Double lines are the long jumper wires that chains each panel with another

Now here is more info related to the Display

Pixels per Panel is 32 (W)*16 (H) dots
The board has 4 panels per chain
The board has 2 chains
So 8 panels in total
So the total resolution is 320(w)x32(h)

The pin interface is called HUB12, I have interfaced it with Arduino Uno


Marking on the PCB	HUB12 pinout at the datasheet	Arduino Uno Pin Interface

Here is where How you should connect Arduino Uno with the Display

So you connect the Arduino Uno to the HUB12 interface to the panel located at [0,0] position

Notice Panel 4 is chained to Panel 5 HUB12 interface by long jumper wire

The Connection between HUB12 and Arduino Uno is

Ref: http://cdn.shopify.com/s/files/1/0045/8932/files/DMDCON_DMDConnector.pdf?100730

HUB12	Arduino
nOE	9
A	6
B	7
CLK	13
SCLK	8
R_DATA	11
GND	GND

MOST Important: Use an External power Supply like this to power up the Display Board. Arduino is just for applying the logic. Don’t ever think it can power up the display board 😄

Now let’s prepare the Arduino Code

At first, we have to install the libraries

Download this library https://github.com/freetronics/DMD

Extract it and copy it to the Arduino libraries folder for example in my case “/home/ayx/Arduino/libraries”

2. Open Arduino IDE and Install “TImerOne” Library using the “manage libraries” option

Open Dmd_demo.ino sketch

Change The code snippet like this

//SPI.h must be included as DMD is written by SPI
#include <SPI.h>
#include <DMD.h>
#include <TimerOne.h>
#include "SystemFont5x7.h"
#include "Arial_black_16.h"
#include "Droid_Sans_24.h"

//Fire up the DMD library as dmd
#define DISPLAYS_ACROSS 4
#define DISPLAYS_DOWN 2
DMD dmd(DISPLAYS_ACROSS, DISPLAYS_DOWN);

void ScanDMD()
{
dmd.scanDisplayBySPI();
}
void setup(void)
{
Timer1.initialize( 3000 );//period in microseconds to call ScanDMD.
Timer1.attachInterrupt( ScanDMD );//attach the Timer1 interrupt to scan
dmd.clearScreen( true ); //clearthe DMD pixels held in RAM
dmd.selectFont(Droid_Sans_24);
}
void loop(void)
{
dmd.clearScreen( true );
delay(2000);
dmd.drawMarquee("Scrolling Text",14,(32*DISPLAYS_ACROSS)-1,6);
}

Compile it and upload you, if everything is okay then you will see a large text scrolling

SPI (Serial Peripheral Interface ) communication between 2 AVR mcus

SPI stands for Serial Peripheral Interface

SPI is a communication protocol used to communicate between microcontrollers and other devices, like other microcontrollers, external EEPROMs, DACs, ADCs, etc. With this interface, you have one Master device which initiates and controls the communication, and one or more slaves who receive and transmit to the Master

Project description

This project shows SPI communication between 2 atmega8 mcus in which 1 atmega8 is master and the other one is a slave.

Here two MCU will transfer the byte to each other via SPI and will show the received byte at the output port

Sequence

master atmega8 will transfer 112=01110000 to the slave atmega8
slave atmega8 will transfer 21=00010101 to the master atmega8
so master atmega8's PORTD should show 21=00010101
So slave atmega8's PORTD should show 112=01110000
master and slave prepare the data to be sent in their respective shift registers & the master generates the required clock pulses on the SCK line. MSB goes first.

ckt & codes are here : https://drive.google.com/file/d/0B8PCKc-8AIcDMEdOa3NwZnhVeWM/edit?usp=sharing

4x4 matrix keypad interfacing with atmega8

This project shows how 16 keys are multiplexed by 4x4 matrix way i.e no of rows: 4 & no of columns: 4 & interfaced with an AVR mcu.

Atmega8 is used here along with a character LCD to show the pressed key value of the matrix keypad.

Scienceprog.com 's LCD library is used

ckt & codes are here : https://drive.google.com/file/d/0B8PCKc-8AIcDYjJ5ZjNNcVVQR2M/edit?usp=sharing

Dot Matrix Display interfacing with Microcontroller

" Sync electronics" - message is displayed at Dot matrix by scrolling using 74HC595 shift register .... the circuit given is just for showing how 2 dot matrix units should be connected to a microcontroller through the shift register. If more dot matrix displays are needed then more shift registers are needed.

Note: Circuit will not simulate; the circuit is just for showing the connections required; one has to build the circuit in real and then test

8*8 Dot matrix

5*7 Dot matrix

Ckt & codes are here : https://drive.google.com/file/d/0B8PCKc-8AIcDNjU3ZWc2ZEF0VDg/edit?usp=sharing

74HC595 shift Register interfacing with atmega8

This is a simple project for interfacing the 74HC595 shift register with the Atmega8 microcontroller. An 8bit pattern is displayed by writing 8bit unsigned int type data to 74HC595 ic

this project will help understand multiple DOT matrix displays interfacing with the microcontroller.