value at fixed memory address

[redkofka]

Posted on July 03, 2012 at 08:32

hi i want to place value - ''address of station'' at fixed memory address

without specifed address its look like

&sharpdefine mcu_address 0x03

i found - it may looks like

&sharpdefine mcu_address         (*((volatile unsigned long *) 0x20000000))

mcu_address = 0x03;    //here i have syntax error

i am using coocox ide...

thanks for all ideas ...

#value-address

[Tesla DeLorean]

Posted on July 03, 2012 at 12:39

Both Keil 4.53 and GCC 4.7.1 are tolerant of that, perhaps a more complete exemplar that demonstrates the issue would help. Is it the compiler or the IDE reporting this error, which version of GCC?

The typical method is

unsigned long *foo = (unsigned long *)0x20000000;

*foo = 12345;

foo[1] = 67890;

[Andrew Neil]

Posted on July 03, 2012 at 23:47

''here i have syntax error''

 

You need to show the full text of the error.

And, as clive1 says, you also need to show a complete example.

[redkofka]

Posted on July 04, 2012 at 07:38

ok -

so i used this in my code and it works great :

#define rts_1        GPIOA->ODR |=  (1 << 12);                //rs485

#define rts_0        GPIOA->ODR &= ~(1 << 12);            //rs485

#define adresa 0x03              

then i have something like rx_packet 24byte - adress of mcu is on rx_packet[2]

in code i check if address is valid

if  (adresa ==rx_packet[2] ){Decode_Packet(p);}

/***************************************/

when i used this definition

#define mcu_address         (*((volatile unsigned long *) 0x20000000))

mcu_address = 0x03;    //here i have syntax error -it show ''?'' in coocox and in compile log i have

       [cc] C:\CooCox\CoIDE\workspace\DMA\main.c:93: error: expected identifier or '(' before 'volatile'

       [cc] C:\CooCox\CoIDE\workspace\DMA\main.c:93: error: expected ')' before numeric constant

so i tried used clive's example

unsigned long *foo = (unsigned long *)0x20000000;

*foo = 12345;    // error: conflicting types for 'foo'

foo[1] = 67890; //  error: conflicting types for 'foo' and  error: invalid initializer

i use gcc arm-none-eabi-gcc-4.4.1

all in all i only want to have const or variable of device address on my memory adress where i want ....

thanks for yours posts guys ...