Moving Message Dot Matrix Display

Transcription

1 Moving Message Display N. SHARMA EM TESTED EM TESTED E M TESTED MUDIT AGARWAL Moving Displays are perfect for all sort of business establishments like Airports, Clinics, Hospitals, Hotels, Restaurants, Retail Shops, Banks, and other such places to get maximum notice of people. These displays attract customers to look at the display with interest and your scrolling message also is conveyed simultaneously. Very good advertising results are obtained from these unique displays with most recent technology. Hardware Power Supply 5 volt regulated DC is obtained from 9V, 500mA transformer, diode, capacitor and regulator IC 7805 as shown in fig.. In this system eight digit moving dot matrix display is divided into two four digit part and each part is derived by separate power source. Microcontroller The PIC 6F877A has 40 pins. Operating speed: 9 V Transformer 500 ma 0V A.C. 9 V Transformer 500 ma 0V A.C. D D D6 D7 D D4 D5 D8 Fig. : Circuit diagram of Power Supply DC MHz clock input Up to 8K x 4 words of Flash Program Memory, Up to 68 x 8 bytes of Data Memory (RAM),Up to 56 x 8 bytes of EEPROM Data Memory. Module This circuit uses common anode 5x7 dot matrix module. Pin diagram of dot matrix module is shown in fig.. Driver IC IC 7805 C I 7805 C6 DIR G Enab le A B A B A 4 B 5 B A4 A5 VDD= 5 V DC supply 0 = 5 V DC supply 0 6 B5 A6 7 R C R4 R R 5 X 7 Common Anode R5 R7 R4 R6 Fig. : Pin diagram of Module Pin out of 7445 is shown in fig.. These octal bus transceivers are designed for asynchronous t w o - w a y communication between data buses. The control function implementation minimizes external timing requirements. The device allows data transmission from the A Bus to the B Bus or from the B Bus to the A Bus depending upon the logic level at the direction control (DIR) input. The enable input (G) can be used to disable the device so that the buses are effectively isolated. Bi- Directional bus transceiver in a high-density -pin package -STATE outputs drive bus lines directly B6 A7 B7 A8 B8 Fig. : Pinout of 7445 Driver IC

2 VDD R S C7 C I I I I IC6 IC Module Module Module Module IC IC9 IC0 IC I Module 5 Module 6 Module 7 Module 8 Fig. 4 :Circuit diagram of Moving Message Display PNP inputs reduce DC loading on bus lines Hysteresis at bus inputs improve noise margins Typical propagation delay times, port-to-port 8 ns Typical enable/disable times 7 ns IOL (sink current) 4 ma IOH (source current) -5 ma Control of Moving Message Display System based on PIC6F877A microcontroller, each module of dot matrix display consist of seven rows namely R,R,R,R4,R5,R6,R7 and five column C,,,,. Row of dot matrix module is connected to PORTB of microcontroller R is connect to LSB of PORTB via driver IC 7445 because microcontroller would not be able to sink all current of 40 LED, even if we use display in multiplexed mode then also it can hardly sink 5 LED current. All column of different dot matrix module

3 Fig. 5 : PCB layout for Microcontroller based Moving Message Display are drive by 7445 IC since single pin of controller cannot source sufficient current to drive seven LED simultaneously. This circuit uses common anode display so to display different characters different combination of values are required at PORTB provided PORTC is at HIGH logic. Refer Table.

4 Do t Matr ix Module Fir s t 4 dot matrix module CONSTRUCTION Ic 7805 C6 D5 D8 D6 D7 V AC Input D D D D4 C Ic 7805 S e co nd 4 do t er7 m atri x mo du l R6 R5 R4 R R R IC8 R S I R R R R4 R5 R6 Do t M arx ti Mo due l 8 C I I C Dot Ma t rix Mod u le 7 C IC C7 I I C D ot M atrix Module C8 Dot M a t r ix 6 Module C IC0 IC6 C Dot Mat r ix Mo dul e D o t Mat r ix M o dul e 5 C Ic9 IC7 C Do t Matrix Module 4 Fig. 6 : Component layout for Microcontroller based Moving Message Display Circuit diagram is shown in figure 4 PCB layout is shown in figure 5 and component layout in figure 6. Software BSF PCLATH, 4 GOTO _main

5 Character Table PORTB Data SEMICONDUCTOR DEVICES IC,I 7805,5 volt regulator I To I 7445 I PIC6F877A microcontroller D-D8 n4007 as rectifier CAPACITORS C, 000uf/5V,,, C6 0.uf C7,C8 pf RESISTORS R Component List 0K MISCELLANEOUS TXFR, TXFR 9 volt/500 ma Transformer 4 MHZ S Push To ON Switch 8 Numbers common anode module _Datacall: ;Electronics Maker.C,965 :: Datacall(void) ;Electronics Maker.C,968 :: CONSTRUCTION v o i d x=0; For rest of the code, at : info@electronicsmaker.com or visit us at : Don t miss the opportunity SUBSCRIBE NOW! Name... Address Phone :... Mobile :... (If any)... I am/we are sending a sum of RS....in cash/by D.D./M.O./Cheque Indian Postal Order No.... in favour of M/s EM MEDIA PVT. LTD. payable at Delhi. On Out side Delhi Cheques Please add. Rs. 5/-. SUBSCRIPTION RATES Period Years Five Three Two One Actual Amount You Save Net Amount SUBSCRIPTION FORM YES I WOULD LIKE TO SUBSCRIBE TO electronics maker I UNDERSTAND THE SUBSCRIPTION CHARGES FOR Electronics Maker BCF STATUS, RP BSF STATUS, RP0 CLRF Datacall_x_L0, ;Electronics Maker.C,969 :: for(i=0;i<0;i) CLRF Datacall_i_L0, L_Datacall_5: MOVLW 0 SUBWFDatacall_i_L0, 0 BTFSC STATUS, C GOTO L_Datacall_6 ;Electronics Maker.C,97 :: x=0; CLRF Datacall_x_L0, ;Electronics Maker.C,97 ::q=; MOVLW MOVWF Datacall_q_L0 ;Electronics Maker.C,97 :: PORTC=0xFE; MOVLW 54 BCF STATUS, Rp0 MOVWF PORTC ;qq.c,974 :: do L_Datacall_8: One Year Sub. sub. for month. Three Year Sub. sub. for 6 month. Two Year Sub. sub. for 4 month. SPL. OFFER Five Year Sub. sub. for 0 month. Mail Your Subscription Payment to EM Media Pvt. Ltd. Head Off. :, nd Floor, Sagar Plaza-, Plot No.-6, Road No.-44,Pitam Pura, New Delhi-004 Ph. : info@electronicsmaker.com