Timer 0 and Timer 1 of the AT89S52

[Ogu Reginald]

I want to use either Timer0 or Timer1 of the AT89S52 microcontroller to measure external pulse. While reading, I came across an example that tries to set up timer0.

The example is using a frequency of 24MHz.
Below is a part of the code.
TMOD=0x52; // timer 0 mode 2, counter 1 mode 1
THO=5;//makes the timer to overflow every 125 uS (divide by 250).

Please can someone help me and explain the two lines above.
If there are equations to help me, please attach. I want the timer to reload every second and I want to use 12MHz.
If I want to use Timer 1 Mode 2, what will I use.

 

[milan.rajik]

Try these links.

https://8051-microcontrollers.blogspot.in/2013/02/counters-and-timers.html#.VU7c9vmqpBd
https://www.dauniv.ac.in/downloads/EmbsysRevEd_PPTs/Chap_2Lesson03EmsysNew.pdf

https://www.youtube.com/watch?v=0SZPr4iGACg

 

[Ogu Reginald]

Thank you very much.
I will upload the code I am writing after reading and watching the video very soon.

 

[Ogu Reginald]

This a part of my entire code.
The timer 1 is intended to generate a 1sec delay,
during the 1 sec delay,
timer 0 will be counting the frequency of the pulse connected to it.
When TF1 is raised (after 1 sec),
The number of pulse (frequency) is displayed on an LCD.
Please don't bother on the timer0 and display sub programs, they have been well written.
My concern and problem is to generate 1 sec delay (I don't know the exact value to load to the TL1 and TH1).
Please carefully check the code for me, Thanks.
Below is the code:

Timer1 ()
{
TR1=0;
TMOD &=0x01; // timer 1 set to mode 1
TL0=0x00;
TH0=0x00;
TF1=0;
TR1=1;
while (TF1==0)
{
timer0 (); //count the frequency of the pulse connected timer 0
}
if (TF1==1)
{
Display (); //displays the d (d= Frequency/7)
}
}