Digital Signal Processing Lab No. 2 Vietnamese Text Display.pdf

2: Vietnamese Text Display Lecturer: Prof... ABSTRACTStick Development Tool and briefly outline the process of implementing the display of an desired Vietnamse texts on LCD.. The displ

HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY

FACULTY OF ELECTRICAL AND ELECTRONIC ENGINEERING

DIGITAL SIGNAL PROCESSING

LAB No 2: Vietnamese Text Display

Lecturer: Prof Dr LE TIEN THUONG

Course ID: EE2016

Class: TT06 Group: 5

Table of Contents

I. ABSTRACT 1

II INTRODUCTION 1

III PROBLEM 1

IV APPROACHES 2

V PROCEDURES 3

VI RESULTS & CODES 4

VII CONCLUSION 16

VIII REFERENCES 16

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I ABSTRACT

Stick Development Tool and briefly outline the process of implementing the display of

an desired Vietnamse texts on LCD

LCD of TMS320C5515/35 is a 96x16 OLED display screen which has 96

columns and 16 rows of pixels The display screen is divided into two rows (in the presented codes, pages or lines) , so actually we have two 96x8 pages to display a text

For this project, to illustrate each character, we need 5x8 pixels To keep the space between characters, we use only most right 4x7 pixels for deriving the sets of desired characters Each led in LCD is activated by setting to bit HIGH that passing

to sets of DATA rows Therefore, an array of 4 HEX codes are recommended to

illustrate each proper character The picture below will clearly show the rules of writing on LCD

Due to the limitation of memory, the screen only displays 128 columns for each page Find a solution for showing full text in one-time display.

Capture the result and write a report

In this project, all deriving codes are based on sample source files in

lcd-osd9616, in oled_test.c In order to satisfy the tasks:

Firstly, to print out a character, we mainly used the pre-defined function in C

files, Int16 printLetter ():

Int16 printLetter(Uint16 l1,Uint16 l2,Uint16 l3,Uint16 l4)

Where l1 consider as A0, l2 as A1, l3 as A2, l4 as A3

Noticably,writing the character backwardly is MUST due to its physically chip memory operations

printLetter(0x40,0x70,0x48,0x30); // a

printLetter(0x00,0x78,0x48,0x78); // o

printLetter(0x00,0x60,0x20,0x78); // h

printLetter(0x41,0x36,0x08,0x7f); // K

Another point is that the pointer to writing address in SDRAM are

automatically increased so no further action to cursor is needed

Secondly, to make an on-screen running display, some following codes must be

called, with the efforts of sending commands to LCD hardware

/* Set vertical and horizontal scrolling */

cmd[0] = 0x00;

cmd[1] = 0x29; // Vertical and Right Horizontal Scroll

cmd[2] = 0x00; // Dummy byte

cmd[3] = 0x00; // Define start page address

cmd[4] = 0x01; // Set time interval between each scroll step

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Eventually, to repair the limitation of SDRAM, our solutions are to seperate

desired texts into various pieces and display different parts gradually on screen as wereset the pages An USBSTK5515_waitusec( Uint32 usec ) system library functions are necessary as the system-clock is so fast that our human’s eyes are able to

oberserve the LCD screen’s change

USBSTK5515_waitusec( 7000000 );

/*Re-fill page 0 */

OSD9616_send(0x00,0x00); // Set low column address

OSD9616_send(0x00,0x10); // Set high column address

OSD9616_send(0x00,0xb0+0); // Set page for page 0 to page 5

Step 1: Use Charset Editor to simulate the letters display on OLED in order to

get the addresses of pixels of that letter For example, the letter T will give the

address set of (0x01;0x7F;0x01;0x01)

Step 2: Modify the C program (oledtest.h) to display the required characters on

OLED, based on the address set of each character obtained in step 1 Here the

memory of the OLED is limited so we set the OLED to refresh some seconds (delete old text and overwrite it with new text)

The main program is running in the function oled_test() Descriptions

as belowed FlowChart:

Step 3: Capture the results.

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VI RESULTS & CODES Results:

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C-file Derived Codes:

/*

* Copyright 2010 by Spectrum Digital Incorporated

* All rights reserved Property of Spectrum Digital Incorporated */

/*

* OSD9616 OLED Test

*

*/

#include"usbstk5515.h"

#include"usbstk5515_i2c.h"

#include"usbstk5515_gpio.h"

#include"lcd.h"

#define OSD9616_I2C_ADDR 0x3C // OSD9616 I2C address

/* - *

* *

* Int16 OSD9616_send( Uint16 comdat, Uint16 data ) *

* *

* Sends 2 bytes of data to the OSD9616 *

* *

* - */

Int16 OSD9616_send( Uint16 comdat, Uint16 data )

{

Uint8 cmd[2];

cmd[0] = comdat & 0x00FF; // Specifies whether data is Command

or Data

cmd[1] = data; // Command / Data

return USBSTK5515_I2C_write( OSD9616_I2C_ADDR, cmd, 2 ); }

/* - *

* *

* Int16 OSD9616_multiSend( Uint16 comdat, Uint16 data )

* * *

* Sends multiple bytes of data to the OSD9616 *

* *

* - */

Int16 OSD9616_multiSend( Uint8* data, Uint16 len ) { Uint16 x; Uint8 cmd[10]; for(x=0;x<len;x++) // Command / Data {

cmd[x] = data[x]; }

return USBSTK5515_I2C_write( OSD9616_I2C_ADDR, cmd, len ); }

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* *

* - */

Int16 printLetter(Uint16 l1,Uint16 l2,Uint16 l3,Uint16 l4) { OSD9616_send(0x40,l1); OSD9616_send(0x40,l2); OSD9616_send(0x40,l3); OSD9616_send(0x40,l4); OSD9616_send(0x40,0x00); return 0; } /* - *

* *

* Int16 oled_test() *

* *

* Testing function for the OSD9616 display *

* *

* - */

Int16 oled_test() { Int16 i; Uint8 cmd[10]; // For multibyte commands /* Initialize I2C */ USBSTK5515_I2C_init( );

/* Initialize LCD power */ USBSTK5515_GPIO_setDirection( 12, 1 ); // Output USBSTK5515_GPIO_setOutput( 12, 1 ); // Enable 13V

/* Initialize OSD9616 display */

OSD9616_send(0x00,0x00); // Set low column address

OSD9616_send(0x00,0x10); // Set high column address

OSD9616_send(0x00,0x40); // Set start line address

cmd[0] = 0x00 & 0x00FF; // Set contrast control register

cmd[1] = 0x81;

cmd[2] = 0x7f;

USBSTK5515_I2C_write( OSD9616_I2C_ADDR, cmd, 3 );

OSD9616_send(0x00,0xa1); // Set segment re-map 95 to 0

OSD9616_send(0x00,0xa6); // Set normal display

cmd[0] = 0x00 & 0x00FF; // Set multiplex ratio(1 to 16)

cmd[1] = 0xa8;

cmd[2] = 0x0f;

USBSTK5515_I2C_write( OSD9616_I2C_ADDR, cmd, 3 );

OSD9616_send(0x00,0xd3); // Set display offset

OSD9616_send(0x00,0x00); // Not offset

OSD9616_send(0x00,0xd5); // Set display clock divide ratio/oscillator frequency

OSD9616_send(0x00,0xf0); // Set divide ratio

cmd[0] = 0x00 & 0x00FF; // Set pre-charge period

cmd[1] = 0xd9;

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OSD9616_send(0x00,0x00); // Set low column address

OSD9616_send(0x00,0x10); // Set high column address OSD9616_send(0x00,0xb0+0); // Set page for page 0 to page 5 for(i=0;i<128;i++)

{

OSD9616_send(0x40,0x00);

}

/* Write to page 0 */

OSD9616_send(0x00,0x00); // Set low column address

OSD9616_send(0x00,0x10); // Set high column address OSD9616_send(0x00,0xb0+0); // Set page for page 0 to page 5for(i=0;i<5;i++){

for(i=0;i<5;i++)

{

OSD9616_send(0x40,0x00); // Spaces

}

for(i=0;i<5;i++)

{

OSD9616_send(0x40,0x00); // Spaces

}

OSD9616_send(0x00,0x00); // Set low column address

OSD9616_send(0x00,0x10); // Set high column address OSD9616_send(0x00,0xb0+1); // Set page for page 0 to page 5 for(i=0;i<128;i++)

OSD9616_send(0x00,0x00); // Set low column address

OSD9616_send(0x00,0x10); // Set high column address OSD9616_send(0x00,0xb0+1); // Set page for page 0 to page 5for(i=0;i<5;i++){

for(i=0;i<5;i++)

{

OSD9616_send(0x40,0x00); // Spaces

cmd[3] = 0x00; // Define start page address

cmd[4] = 0x03; // Set time interval between each scroll step cmd[5] = 0x01; // Define end page address

cmd[6] = 0x00; // Vertical scrolling offset

OSD9616_multiSend( cmd, 7 );

OSD9616_send(0x00,0x2f);

/* Keep first 8 rows from vertical scrolling */

cmd[0] = 0x00;

cmd[1] = 0x00; // Set Vertical Scroll Area

cmd[2] = 0x10; // Set No of rows in top fixed area

cmd[3] = 0x00; // Set No of rows in scroll area

OSD9616_multiSend( cmd, 4 );

return 0;

}

VII CONCLUSION

In this lab, we have successfully designed the required

Vietnamese text on charset editor and wrote a program to display

them on the OLED screen of the ezDSP8535 development kit

However, there are some minor imperfections in our text, which we

can improve in the next labs

Digi-Key Electronics (digikey.com)

- TMS320C5515 eZdsp USB Stick Development Tool, access from:

C5515 eZdsp (ti.com)

Evaluation board | TI.com

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