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.
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.
The three steps needed to write the software are:
Step 1: Find keyboard/display command word.
Step 2: Find program clock command word
Step 3: Find Read FIFO/sensor RAM command word.
Step 4: Find Write FIFO RAM command word.
Interrupt service routine:
Flowchart for Source Program and Interrupt Service Routine
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