Generate and display BCD down counter

Statement:Write a program for displaying BCD down counter. Counter should count numbers from 99 to 00 and it should increment after every 1 sec. Assume operating frequency of 8085 equal to 3MHz. Display routine is available.

Source program 1:

• LXI SP, 27FFH : Initialize stack pointer
• MVI C, 99H : Initialize counter = 99
• BACK:CALL Display : Call display subroutine
• CALL Delay : Call delay subroutine
• ADI 99H : See Addition below
• DAA : Adjust for decimal
• CPI 99H : Compare with last count
• JNZ BACK :If no, repeat
• HLT

Source Program 2:

• LXI SP, 27FFH : Initialize stack pointer
• MVI C, 99H : Initialize counter = 99
• BACK: CALL Display : Call display subroutine
• CALL Delay : Call delay subroutine
• MOV A, C : Get count
• ANI 0FH : Check for lower nibble
• JNZ SKIP : If it is not 0FH go to skip
• MOV A,C : Else get the count
• SBI ,06 : Subtract 06
• MOV C,A : Store the count
• DCR C : Decrement count
• CPI 99H : Check it for last count
• JNZ BACK : If not, repeat
• HLT : Stop