Question

Assuming the oscillator frequency is 12MHz. What is the machine cycle of 8051? Please write a delay- subroutine to generate about 20ms delay . Answer:

Answer 1

Here is the solution for above question.

covery, Oscillator frequency 12 MHz time period of 1 clock cycle 1/f = lillele time period of IT state &x 1/2 rece = // usec Time penod of im/c = 6.7 = 6* 6xĆ { pesce : IMRE I machine cycle I herec.

Sub routine to generale 2018 Delay: Machine Cycles DELAY : MOV R2 , #20 ܝܙ AGAIN : MOV R3, #250 ܝܕ HERE ! NOP NOP ܝܢ 2 2 DTNZ R3, HERE DSNZ R2, AGAIN 2 RET HERE loop 250 (1+1+2) = 1000 MIC 20 (1000+1+2) 20060mic AGAIN Loop 20060 + 1 + 2 = 20063 mic whole program 20063 X INS To tal Delay TB E 20.06 ms

Hope it helps. Thank you.