Keil compilation and bit-band operation issues

bigbat

Keil compilation and bit-band operation issues [Copy link]

According to the records, STM32G431 uses the cortex-M4 core, which should be able to use the bit-band operation address function. Now I want to use bit-band operation, but I check the keil project compilation definition. IRAM=20000000, SIZE=8000, the on-chip SRAM is 32K in size, and now I am wondering, does the keil variable memory allocation start from 20000000? Or 20008000?

Also, what are the uses of IRAM2 memory?

Experts please answer!

bigbat

Sorry this question is so stupid!!! I figured it out myself. Any variable can use bit-banding operation as long as it is in the SRAM area or peripheral address!

Just use

#define BITBAND(addr, bitnum)((addr & 0xF0000000)+0x2000000+((addr & 0xFFFFF)<<5)+(bitnum<<2))　　
#define MEM_ADDR(addr) *((volatile unsigned long *) (addr))
These two macros will do.

Thank you everyone!

bigbat

#define BITBAND(addr, bitnum)((addr & 0xF0000000)+0x2000000+((addr & 0xFFFFF)<<5)+(bitnum<<2))　　#define MEM_ADDR(addr)  *((volatile unsigned long *) (addr))

uint8_t bitband = 0x0;
//执行到此处死机了！！！
MEM_ADDR(BITBAND(bitband,2)) = 0x1; 
printf("bit=%02x\r\n",bitband);

The program can be compiled, but it freezes when it reaches MEM_ADDR(BITBAND(bitband,2)) = 0x1;

MikeCai

You can also read the G431 information, or even simpler, use cubeMX to automatically generate the bare metal initial keil code, don’t you have it all?

MikeCai

Automatically generate code, you don't have to worry about where the code starts, where it is placed, size, etc. Reduce development time