Hello, Can someone explain what it means??
#define IOPIN0 (*(volatile unsigned long *)(GPIO_BASE_ADDR + 0x00))
The controller using is LPC23xx/24xx.
BR Chethan
No. You really should read up about volatile.
You seem to think about external declarations, which is something completely different.
Didn't you consider the hints I left about the need for volatile because of the difference between a normal RAM variable and a special function register? Volatile is even part of non-technical English. Nitroglycerin is volatile, as is the situation in Ukraine.