hi,

the timer 0 interrupt occur and jump to the interrupt rountine(these rountine just do not affect the I/O).

That`s good but what is about registers/variables/SFRs which are used both with timer ISR and SPI subroutines?

However, SPI is affected by Timer interrupt.

Please post here the full code of the timer 0 interrupt service routine.

Regards,
Oleg