Write a program to count continuously in hexadecimal from FFH to 00H in a system with clock frequency 0.5 microseconds. Use register C to set up a delay of 1ms between each count and display output at one of the output ports.
- The hexadecimal counter is set by loading a register with starting number and decrementing it till zero is reached and then again decrementing it to will produce -1, which is two’s complement of FFH. Hence, the register again reaches FFH.
- The 1ms time delay is set up by the procedure shown in flowchart-
The register is loaded with appropriate number such that the execution of above loop produces a time delay of 1ms.
|2000H||MVI B, FFH|
|2003H||MVI C, COUNT|
|2009H||MOV A, B|
The C register is the time delay register which is loaded by a value COUNT to produce a time delay of 1ms.
To find the value of COUNT we do-
TD = TL + TO where- TD = Time Delay TL = Time delay inside loop TO = Time delay outside loop
The delay loop includes two instructions- DCR C (4 T-states) and JNZ (10 T-states)
So TL = 14*Clock period*COUNT
Delay outside the loop includes-
DCR B : 4T
MVI C, COUNT : 7T
MOV A, B : 4T
OUTPORT : 10T
JMP : 10T
Total : 35T
TO= 35*Clock period => 17.5 microseconds
So, 1ms= (17.5+ 7*COUNT)microsecond
- 8085 program to convert a hexadecimal number into ASCII code
- 8085 program to convert an 8 bit BCD number into hexadecimal number
- Program for hexadecimal to decimal
- 8086 program to convert a 16 bit decimal number to Hexadecimal
- 8085 program to add two 8 bit numbers
- 8085 program to add two 16 bit numbers
- 8085 program to add 2-BCD numbers
- 8085 program to multiply two 16-bit numbers
- 8085 program to divide two 16 bit numbers
- 8085 program to divide two 8 bit numbers
- 8085 program to reverse 16 bit number
- 8085 program to add numbers in an array
- 8085 program to swap two 8-bit numbers
- 8085 program for Binary search
- 8085 program to multiply two 8 bit numbers
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to firstname.lastname@example.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.
Improved By : Kartikaybhutani