Mapping of Internal Registers in ANSI-C

[jose]

I would like to know if this implementation works with CCS for PIC. The reason why i dont want to use #byte is because of the porting issues.

Please suggest me the best method to map io's and yet portable to all platforms


/*** PORT_B ***/
typedef union {
char BB;
struct {
char BIT_7 :1;
char BIT_6 :1;
char BIT_5 :1;
char BIT_4 :1;
char BIT_3 :1;
char BIT_2 :1;
char BIT_1 :1;
char BIT_0 :1;
} Bits;
}PORTB;

extern volatile PORTB PORT_B @ 0x0001;


or can somebody explain me what "#byte" implemented.


Thank You.

[PCM programmer]

The following code would be more portable than #byte statements,
but I have to ask, how often do you plan to change compilers ?
Even if you're making a product that is intended for use with
different compilers, I think it would be better to port it to each
compiler than to try to debug some "universal" source code.
Look at Peter Anderson's website.
http://www.phanderson.com/PIC/PICC/index.html
He tries to make his code be semi-universal, by avoiding the
use of the CCS delay_ms(), etc., functions. But by doing so
he gives up the flexibility to change the crystal frequency
and have the delay functions automatically be adjusted for
the new frequency. Even he uses the #byte statements.
See his register definitions file.
http://www.phanderson.com/PIC/PICC/CCS_PCM/defs_f84.html
So my main question to you would be, why bother ?

[jose]

Thank you for the advice,

But how can i access bits in the registers using the similar method.

Thank you
Jose

[Mark]

For portability you shouldn't be using PORTB. Instead, you should be using something more descriptive like "data_port". All of these declarations should be in a header file and you would use a different header file for each compiler.

[jose]

Thank you for your advice Mark,

I hope this implementation would work on all the platforms and it doesnt take up the ram area.

Please comment on this implementation.

Thank you

regards
Jose



typedef volatile char SP;

typedef union {
SP BB;
struct {
SP BIT_7 :1;
SP BIT_6 :1;
SP BIT_5 :1;
SP BIT_4 :1;
SP BIT_3 :1;
SP BIT_2 :1;
SP BIT_1 :1;
SP BIT_0 :1;
} Bits;
}PORTB;



#define REG_PORTB ((PORTB *)0x00)



void main() {
.......
.....

REG_PORTB->Bits.BIT_1 = 0;
REG_PORTB->BB = 0;

}

[Mark]

This is how I would do it

http://www.ccsinfo.com/forum/viewtopic.php?t=20186