Hello
I found a similar problem to Christian's, but using the PWM module from
the 5329.
I have solved it creating a driver to access the PWM registers from the
kernel.
But I am yet intrigued by it. I was not able to found why these user
registers were not accesible from userspace. I am using an old 2.16.17
uclinux. I revised SCM PACRx registers and they are all filled with 0
(giving user access, I think). Someone suggested me a cache entry
restriction, but I only can see SDRAM caching at the start code.
What other thing can limit that access?
Thank you,
Jose
El 24/10/2012 3:38, Greg Ungerer escribió:
Hi Christian,
On 24/10/12 01:06, Christian Gieseler wrote:
We have to activate dithering in our Coldfire 5329 device. But it
seams,
that I cant even read the register values of PLL Control Register
(PCR) and
PLL Modulation Divider Register (PMDR). The registers should be user
readable and writable.
Why do you think they should be user space read/write?
But it seems that I get a bus error because the
values do not match the written ones or the reset values if I don┤t
write
something.
That would seem to indicate that those registers are not user space
read/write.
Check your settings of the PACRx registers (Peripheral Access Control
Registers). They power up with the supervisor only access bit set,
so unless you have changed them you won't get user access.
Regards
Greg
#define GT_REG_READ_SHORT(Reg, pData)
\
*pData = ((volatile unsigned short)*((unsigned short *) (Reg)));
#define GT_REG_WRITE(Reg,
data) \
(*(volatile unsigned long *)(Reg)) =data
#define PLL_PODR 0xFC0C0000
#define PLL_PLLCR 0xFC0C0004
#define PLL_PMDR 0xFC0C0008
int main(int argc, char *argv[])
{
unsigned int RegVal=0;
//GT_REG_WRITE(MCF_PLL_PLLCR,0x0);
GT_REG_WRITE (PLL_PLLCR ,0);
GT_REG_WRITE (PLL_PMDR ,0x5);
//Setze PLL Control Register
GT_REG_WRITE (PLL_PLLCR ,0x87);
GT_REG_READ_SHORT (PLL_PLLCR,(unsigned int*)&RegVal);
printf ("PLLCR has Value=%x\n",RegVal);
return 0;
}
Does someone have a hint how to write and read these registers? Is
something
wrong in my code?
Best regards
Christian
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