Hi Juan,

A lot of RTC chips offer an interrupt which can be used as a long duration timer. More setup is required and your resolution is in minutes when this alarm timer is used (at least on the PCF8563 I've been using).

If you need another timer, like T0 and T1, get a uC that is 8052 compatible which has T2.

Another alternative is to have separate counters in your timer ISR, and when these counters reach specific values, set a flag that is tested in the main loop.

Dennis