8051_timer

This 8051project shows the timer operation for 500 microseconds using Timer0. To simulate circuit in this project, initially activate Mixed Mode simulator from the Schematic Editor window. Simulation can be performed by selecting Run Transient analysis (Oscillograph) from Simulation menu.

In this circuit, Port P1 is set as the output port. An internal timer counts from the specified value to FFFF during the 500-microsecond time. A series of pulses will appear at P1 to indicate the duration of timer operation.

The source code written either in C or Assembly language can be viewed from the code editor window

The program is as shown:

#include<8051.h>

void main()

{

TH0 = 0x0fe; // To get the timer operation for 500µ seconds set T0 as FE5F

TL0 = 0x5f;

TMOD = 0x01; // Mode 1 (16-bit timer mode)

TR0 = 1; // TR0 is set to ‘1’ to turn On Timer 0

for ( ; ; ) // Infinite loop

{

P1_0 = P1_0 ^ 1; // Port1.0 is xor-ed with value ‘1’, which will give complement the previous value

If (TF0==1) // TF0 will set when the timer rolls over

{

TR0 =0; // Reset to turn Off Timer 0

break;

}

}

}

The source code in the code editor window has to be compiled after making any modifications

(editing). Also the code can be debugged during simulation.