hi,

Please show timer 2 initialization code.
Please show interrupts setup (enabling,priority) code as well.

How this interrupt is long in time:

/*timer 1 interrupt used for four 7-segment displays multiplexing*/

Have you calculated its time duration?

By the way,there is possible logic error:

/* timer 2 interrupt used to increment count every 1 msec*/
void inter_2(void) interrupt 5 
{if(P0_0==1)
count1++;
TF2=0;
if((count1%10)==0)
g=3;

Look at

count1++;
if((count1%10)==0)

Assume the variable count1 is uchar (8 bit). What does happen during it rolls over 255? You think that you do set variable g to value 3 at each 10 interrupts of timer 2 (when (P0_0==1)) but in fact it happens at values of count1 equal to: 0,10,20...240,250 and then? Yes, at value 0 (after only 6 interrupts! because there are no uchar values 256..259).

Regards,
Oleg