Basic questions of C code and ISR

[spider7]

Hi Everybody,

Can anybody tell me the about some basic questions.

1. In a C code at what speed the Main routine is executed.
2. At what speed the ISR routine is executed.

The MCU is using internal 4 Mhz. The ISR is confugured at 12.5uS.

Thankyou all

 

[dheena]

its upto your prgram ly...it will execute all the things at same speed ly.....each instruction will take some no.of machine cycles and it is upto the instruction and if you find the sum of those times from your program you can get it...

 

[microlab]

hi
there are many things are to be considered
first of all it depends on the compiler and it's optimization techniques.
how it convert the C code to Assembly and then Hex.the more the code, the more time it will take to exicute the code.
In ISR, there are many context saving techniques which used by the compiler which consumes machine cycle.
in assembly you can exatly predict the time consumed

regards

ml

 

[jayaprakash2020]

very easy to calculate by using formulas. but the time to execute main program and ISR for a single instruction with same machine cycles is same.

 

[nikhilele]

which chip you are using.. we can tell you more one this.. 12.5us seems too short... your main will be interrupted a lot hope your ISR is not very long..