write to buffer

nobody wrote on Friday, December 02, 2005:

MY question is how write something to an ARM7 buffer.
e.g. at webserver  project erverytime LED flashes a counter increments. This variable i need in buffer or somewhere else i can use it  at an other task.

jra01 wrote on Friday, December 02, 2005:

Any global variable (not static) will be available to all tasks.
If the accesses are not atomic (in ARM, a 32 bit read or write is atomic), or if you like software with nice structure, you can write a set of functions to handle your data buffer, and if needed protect it with some semaphore.


nobody wrote on Friday, December 09, 2005:

i tryed to define a global variable ( at main.c infornt of main() but it is not known to any other funktion. it is called u8_t test. at the funtktion i need this variable (cgi.c) i defined extern test but it is still unknown.

where should i define a globla variable i think it is the worng place or the wrong way

i read a global variable is definded in front of main() but i thig this time it is only known in main.c an not any whre else…

nobody wrote on Friday, December 09, 2005:

Don’t know which compiler you are using - but to the C standard what you are doing is correct.

Declare in main.c as u8_t test, then reference in cgi.c as extern u8_t test.

test must NOT be declared static.

nobody wrote on Saturday, December 10, 2005:

this i tryed ( i use Rowley crossstudio) but it is still unkonwn.