Hello, Can someone explain what it means??
#define IOPIN0 (*(volatile unsigned long *)(GPIO_BASE_ADDR + 0x00))
The controller using is LPC23xx/24xx.
BR Chethan
Haven't you looked at the description of the volatile keyword?
What is the difference between a normal memory variable and a register mapped to real hardware? When may a memory variable change content? When may a I/O register associated with processor pins change value? Would that matter to the compiler, when it generates the processor instructions?
Actually i know the concept.
Volatile is used to modify the memory content is existing in different file.
Is it correct ???
For remaining questions i don't have much deep knowledge. Kindly explain me those things also it looks to be interesting :) :)
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.
(making allowances for English as a foreign language)
Well, one common use of the 'volatile' qualifier is to indicate that memory content may bechanged by "another file".
So think how a hardware SFR (special function register) might have similar issues...
Is this essentially the same question as http://www.keil.com/forum/58484 ?