Free Electronic Circuits & 8085 projects

Electronic projects with circuit diagram and 8085 microprocessor projects.

Roll a message – ‘HELL0123’

Statement: Write an assembly language program to roll a message – ‘HELL0123’ from right to left

To roll the above message we have to load 7-segment codes for characters within the message and it is necessary to configure 8279 in right entry mode

76.b-Interfacing of eight 7-segment digits

Step 1: Find keyboard/display command word.

78.b-Roll a message - 'HELL0123'

Note: DD = 10 = 8 8-bit character display right entry.

Step 2: Find program clock command word

78.c-Roll a message - 'HELL0123'

Step 3: Find Read FIFO/sensor RAM command word.

78.d-Roll a message - 'HELL0123'

Step 4: Find Write FIFO RAM command word.

78.e-Roll a message - 'HELL0123'

Source program:

  • LXI B, 6200B : Initialize lookup table pointer
  • MVI C, 08H : Initialize counter
  • MVI A, 10H : Initialize keyboard/display in right entry mode
  • OUT 8IH : Mode
  • MVI A, 3EH : Initialize prescaler count
  • OUT 8IH
  • MVI A, D0H : Clear Display
  • OUT 8IH
  • MVI A, 90H : Initialize 8279 in write display
  • OUT 81H : RAM mode
  • BACK : MOV A, M : Get the 7-segment code
  • OUT 80H : Write 7-segment code in display RAM
  • INX H : Increment lookup table pointer
  • DCR C : Decrement counter
  • JNZ BACK : if count = 0 stop, otherwise go to back
  • HLT : Stop program execution

Flowchart for Source Program

78.f-Roll a message - 'HELL0123'

78.g-Roll a message - 'HELL0123'

 Related Programs (Click down)

Find the 7-segment codes for given numbers

Find the ASCII character

ASCII to Decimal Conversion

HEX to Decimal conversion