Read Data From flash or RAM

harshitha_chiga — Wed, 27 Feb 2019 11:09:04 GMT

I am using a define to read data from and write to flash or ram.

#define REG_READ(address) ((uint8_t)(*(vuint8_t *)(address)))

#define REG_WRITE(address, value) (*(vuint8_t *)(address) = (value))

But I'm unable to understand ((uint8_t)(*(vuint8_t *)(address))) and (*(vuint8_t *)(address) = (value)) this.

Could you please help me out on this? How it is typecasted and what this typecasting actually means.

Thanks in advance!!

Harshitha C B

Re: Read Data From flash or RAM

BlackNight — Wed, 27 Feb 2019 11:20:13 GMT

Welcome to the C programming language :-)

#define REG_READ(address) ((uint8_t)(*(vuint8_t *)(address)))

you can use it as this:

uint8_t val = REG_READ(0x1000);

The macro takes the address (0x1000 in this case) and casts it to a pointer to volatile unsigned 8bit int ((vuint8_t*).

Then it dereferenciates the pointer (* operator) and casts the result to an unsigned 8bit int (uint8_t).

Finally, it assigns it to the variable val.

The WRITE macro is doing the same thing, must with assigning the value to that constant pointer cast.

I hope this helps,

Erich