How access the bitfield of MSP430 in IAR C

bitfield msp430 example

How to access the bitfield of MSP430 using IAR C. for instance, I want to set or reset of any individual bit from c code.

iar msp430 bitfield

Do this defines:

#define bit_test(A,B) (A & B)
#define bit_set(A,B) A |= B
#define bit_clear(A,B) A &= ~B

Then you has just insert the processor header:

#include "msp430x14x.h"

Now if you wanna set bit 0 of any REGISTER of variable simple do it:
bit_set(ANY_REGISTER,BIT0);

For RESET
bit_clear(ANY_REGISTER,BIT0);

for test if bit is set
if (bit_test(ANY_REGISTER,BIT0))
{
}

for test if bit is clear
if (!bit_test(ANY_REGISTER,BIT0))
{
}


Do the same for
BIT1, BIT2, BIT3, BIT4, BIT5, BIT6, BIT7, BIT8, BIT9, BITA, BITB, BITC, BITD, BITE, BITF
These are defined on processor header like it....

#define BIT0 (0x0001)
#define BIT1 (0x0002)
#define BIT2 (0x0004)
#define BIT3 (0x0008)
#define BIT4 (0x0010)
#define BIT5 (0x0020)
#define BIT6 (0x0040)
#define BIT7 (0x0080)
#define BIT8 (0x0100)
#define BIT9 (0x0200)
#define BITA (0x0400)
#define BITB (0x0800)
#define BITC (0x1000)
#define BITD (0x2000)
#define BITE (0x4000)
#define BITF (0x8000)

leomecma

iar msp430 bitfield example

I know this method, but I think this is still not bit access but whole register access

The following is the example of bit accessing:
__no_init volatile union
{
unsigned char IE1
struct
{
unsigned char WDTIE : 1;
unsigned char OFIE : 1;
unsigned char : 2;
unsigned char NMIIE : 1;
unsigned char ACCVIE : 1;
unsigned char URXIE0 : 1;
unsigned char UTXIE0 : 1;
} IE1_bit;
} @ 0x0000;

By including above code into the user code it is possible to access either the whole register or any individual bit (or birtfields) from C code as follows"

//whole register access

IE1 = 0x1234;

//Bitfield accesses

IE1.WDTIE = 1;

I try it but can not success. I don't know why?

bitfield msp430

IAR don't support this modes.


leomecma

chen_Analog,
I believe that you solution is to use macros.

At my proyects with MSP430 I use....

#define RTSon() P3OUT != 0x04 //being bit4 of P3 = 1
#define RTSoff() P3OUT &= ~0x04 //deing bit4 of P3 = 0

then

main()
{
...
...
//now I want RTS=1
RTSon();
....
.....
//now RTS=0
RTSoff();
....
....


}

This example you can to apply to your work
i.e.

Best Regards
FSio