Interfacing of 4x4 Matrix Keyboard and 4 Digit 7 Segment Display - Free Electronic Projects & 8085 Projects

10/1/13Interfacing of 4x4 matrix keyboard and 4 digit 7 segment display - Free Electronic projects & 8085 projects Free Electronic projects & 8085 projects Home Forum Electronic Projects 8085 Microprocessor 8086 Microprocessor Home > 8085 Microprocessor > 8085 programs > Interfacing of 4×4 matrix keyboard and 4 digit 7 segment display Interfacing of 4×4 matrix keyboard and 4 digit 7 segment display Nov - 19 - 2009 Statement: Interface 4 x 4 matrix keyboard and 4 digit 7-segment display and write an tssembly language program to read keycode of the pressed key and display same key on the 7 segment display. HARDWARE FOR 4×4 MATRIX KEYBOARD & 4 DIGIT 7 SEGMENT DISPLAY INTERFACE Fig. shows interfacing diagram. Here, 4 scan lines are sufficient to scan matrix keyboard and to select display digits. Hence decoded mode is used. SOFTWARE FOR 4×4 MATRIX KEYBOARD & 4 DIGIT 7 SEGMENT DISPLAY INTERFACE To display 1 to 8 numbers on the eight 7-segment digits we have to load 7-segment codes for 1 to 8 numbers in the corresponding display locations. 8085projects.info/interfacing-of-4x4-matrix-keyboard-and-4-digit-7-segment-display.html 1/4 info/interfacing-of-4x4-matrix-keyboard-and-4-digit-7-segment-display. Step 4: Find Write FIFO RAM command word. M : Get the 7 segment code OUT 80H : Write 7-segment code in display RAM EI : Enable interrupt RET : Return to main program Related Programs (Click down) 8085projects. 00H : Initialize keyboard/display in encoded OUT 81H : scan keyboard 2 key lockout mode MVI A.html 2/4 .5 SIM : mask other interrupts EI : Enable Interrupt HERE: JMP HERE : Wait for the interrupt Flowchart for Source Program and Interrupt Service Routine Interrupt service routine: MVI A. 34H OUT 81H : Initialize pre-scalar count MVI A. Source program: MVI A. 0BH : Load mask pattern to enable RST 7.10/1/13 Interfacing of 4x4 matrix keyboard and 4 digit 7 segment display . A : 7-Segment code MVI A. 62H : Initialize memory pointer to point MOV L. Step 2: Find program clock command word Step 3: Find Read FIFO/sensor RAM command word.Free Electronic projects & 8085 projects The three steps needed to write the software are: Step 1: Find keyboard/display command word. 80H : Initialize 8279 in write display RAM mode OUT 81H MOV A. 40H : Initialize 8279 in read FIFO RAM mode OUT 81H IN 80H : Get keycode MVI H. info/interfacing-of-4x4-matrix-keyboard-and-4-digit-7-segment-display.10/1/13 Interfacing of 4x4 matrix keyboard and 4 digit 7 segment display .Free Electronic projects & 8085 projects Generate and display BCD up counter with frequency 1Hz Generate and display BCD down counter Generate and display the contents of decimal counter Debug the delay routine Related Posts: Write an ALP using 8085 to evaluate the expression C=A2+B2 Home Appliance Circuits Do It Yourself DIY circuits Remote Control based Circuits Agricultural Automation Circuits LED circuits LED Circuits-1 PC Circuits Interface Circuits-4 Fan circuits-3 555 – Game Circuit-3 Telephone circuits – 1 Interface Circuits-3 New Microcontroller Circuits-1 Device application circuits-4 Fan circuits-9 Telephone communication circuits-2 Video and Audio Circuits-5 LED Circuits-7 Interface Circuits-1 Search Categories 8085 Microprocessor 8086 Microprocessor 555 Circuits Agricultural Automation Circuits Audio Circuits Automotive Circuits Basic Circuits Communication Circuits Control circuits Converting Circuits DIY Circuits Electronic Maintanance Circuits Elevator control circuit Fan circuit 8085projects.html 3/4 . 10/1/13 Interfacing of 4x4 matrix keyboard and 4 digit 7 segment display .info/interfacing-of-4x4-matrix-keyboard-and-4-digit-7-segment-display.html 4/4 .Free Electronic projects & 8085 projects Health care circuits Home Appliances Circuits Integrated circuits Copyright © 2013 Free Electronic projects & 8085 projects | Privacy policy 8085projects.