Dear friends,
i'm doing some code to implement a 8bit parallel port using the PRUSS-ICSS of the AM3359,
and i'm running into troubles because i can't read some DDR values from the C31 constant table address of PRU1.
Obviously i'm previously filling some known data into the right DDR addresses externally from PRUs.
Here is my code snippet:// Clear SYSCFG[STANDBY_INIT] to enable OCP master port
LBCO r0, C4, 4, 4
CLR r0, r0, 4
SBCO r0, C4, 4, 4
//Enable PMAO
LBCO r0, C4, 0x28, 4
SET r0, r0, 1 //set bit 0
SET r0, r0, 1 //set bit 1
SBCO r0, C4, 0x28, 4
// Configure the programmable pointer register for PRU1 by setting c31_pointer[15:0]
// field to 0x50000000. This will make C31 point to 0x80500000 (DDR memory).
MOV r0, 0x50000000
MOV r1, 0x2402C
ST32 r0, r1
LBCO r10, CONST_DDR, 0, 4
// r10 should now contain desired data
The strange thing is that if i run the same code on PRU0 (only changing the offset of CTPPR1 to 2202C)
it run perfectly.
If i run on PRU1 instead i get some uninitialized data from DDR (i can't get the address where it is pointing to)
On both cases on C31 i read "0x80500000" (correct).
Is there any limitation on reading from PRU1 to DDR addresses?
Thanks for any help.
Sandro Viti
