Timer1 question

[sraiderk]

İf I use 16f877 with setting of the timer1 the following

setup_timer_1(T1_INTERNAL|T1_DIV_BY_8); //20MHz cristal


104,857ms time later interrupt occurs. My question is that if I define setup_timer with the same configuration like that

setup_timer_1(T1_INTERNAL|T1_DIV_BY_8 |T1_DIV_BY_8);

interrupt occurs at that time later 104,857*8=838,860ms doesn't it?

[Humberto]

Copied from the Compiler HELP:
_____________________________________________________________
SETUP_TIMER_1( )
Syntax:
setup_timer_1 (mode)
Parameters:
mode values may be:

- T1_DISABLED, T1_INTERNAL, T1_EXTERNAL, T1_EXTERNAL_SYNC

- T1_CLK_OUT

- T1_DIV_BY_1, T1_DIV_BY_2, T1_DIV_BY_4, T1_DIV_BY_8

constants from different groups may be or'ed together with |.
_____________________________________________________________

Hence, in your expresion:

setup_timer_1(T1_INTERNAL|T1_DIV_BY_8 |T1_DIV_BY_8);

T1_DIV_BY_8 | T1_DIV_BY_8 Is Not Valid because you are ORed
two constants of the same group.


Humberto

[Mark]

It will actually be the same since oring something with itself is the same. Read the datasheet on the PIC and you will see the available scalers or divide bys.