Message: 1
Date: Thu, 14 Aug 2008 15:31:06 +0200
From: "Valentin Favreau" <[EMAIL PROTECTED]>
Subject: [uClinux-dev] Controlling GPIO on coldfire
To: uclinux-dev@uclinux.org
Message-ID:
<[EMAIL PROTECTED]>
Content-Type: text/plain; charset="windows-1252"
Hey,
I'm new on uClinux/coldifre and I have a problem with the GPIO.
I found, on the Internet, that I just need to set up a pointer to the I/O
address to access to the I/O but when I run my application on uClinux the
error message "Memory Fault" appears and my application quit.
Here is my simple test code:
#define GPTADR (*(volatile unsigned char *)0x401a001d)
#define GPTADDR (*(volatile unsigned char *)0x401a001e)
int main(void){
GPTADDR = 0xFF;
return 0;
}
I'm working on the DNP/5280 board, Coldfire 5282.
I use this command to compile my code:
m68k-uclinux-gcc –Wall –m5307 –Wl,-elf2flt –Os –o hello hello.c –lc
Does anyone has an idea to solve my problem?
Thanks a lot!
Valentin.
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Valentin
Are you sure your GPIO addresses are correct? It will depend on the
value of the MBAR register. I do direct I/O from userspace. I include
the following header files then access as shown. In my case I am using a
MCF5272 and accessing GPIO port C. There is also a m5282sim.h file.
#include <asm/coldfire.h>
#include <asm/m5272sim.h>
...
pcdat = *(volatile unsigned short *) (MCF_MBAR + MCFSIM_PCDAT);
pcdat &= 0xfeff;
*(volatile unsigned short *) (MCF_MBAR + MCFSIM_PCDAT) = pcdat;
Hope it helps,
Mark
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