REGISTER ACCESS IN MCUXPRESSO

maratheapurv — Wed, 17 Jul 2019 07:02:31 GMT

Hello,

While programming the FRDM-KV31F board with the MKV31f512vll12 controller using MCUXPRESSO

I need to check if the OSCINIT0 bit in the MCG_S (i.e. Multiplex Clock Generation Status) reg is set. Now I am trying to use the and bitwise operator for the same is there any way I can directly access this bit? I know I can access the Status register via a dot operator as it is a member of the MCG structure, but still is there any way I can directly access the specified bit?

Regards,

Apurv.

Re: REGISTER ACCESS IN MCUXPRESSO

jingpan — Wed, 17 Jul 2019 09:12:03 GMT

Hi Apurv,

KV31 hardware doesn't support bit access. You can simulate this function by software. For example,

struct GPIO_BITS {
               uint32_t IO0:1;
               uint32_t IO1:1;
               uint32_t IO2:1;
               uint32_t IO3:1;
               uint32_t IO4:1;
               uint32_t IO5:1;
               uint32_t IO6:1;
               uint32_t IO7:1;
                uint32_t RSVD:8;                       // 31:8 Reserved
};

union GPIO_MASK_REG {
uint32_t all;
struct GPIO_BITS bit;
};

typedef struct
{
__IO union GPIO_MASK_REG MASK;

....

}GPIO_TypeDef;

#define GPIOA ((GPIO_TypeDef *) GPIOA_BASE )

Thus you can access a bit by

GPIOA->MASK.bit.IO7 = 1;

Regards,

Jing

Kinetis MicrocontrollersのトピックREGISTER ACCESS IN MCUXPRESSO

REGISTER ACCESS IN MCUXPRESSO

Re: REGISTER ACCESS IN MCUXPRESSO