DS5250 debbuging problems

int  T0_ISR_CODE(int delay)                    __interupt #1
{
    TH0 = 5;
   TL0      = 7;
}

<endcode>

int  T0_ISR_CODE(int delay)                    __interupt #1
{
    TH0 = 5;
   TL0      = 7;
}

<endcode>

int  T0_ISR_CODE(int delay)                    __interupt #1

That's not Keil C52 syntax!
Besides which:

How do you expect that a parameter can be passed to an ISR?

Where do you expect that the return value for an ISR will go?

What compiler are you using? this is a Keil forum.

If, indeed, you are using Keil C51 you are making a mistake so basic that the only recourse is to work through (NOTE: not 'read') the "getting started guide", or you will only be 5 minutes before you make the next one.

anyhow a Keil interrupt should look like this
void ISX_EI0 (void) interrupt 0 using 1
the 'using 1' may, of course be different.

Erik

or even omitted.