When I write as follows "test code" 32-bit*8 into DDR2 and clock = 166Mhz, have incorrect on as follows "read back result"
but I adjust clock = 96Mhz that it's can correctly.
What codes or registers cause like as this problem, thanks!
test code:
__u32 i,j;
__u32 data[8];
volatile __u32 *ptr = (__u32 *) RAM_BASE;
debug( "\n\r> sdram testing : #" , 0 );
#if 1
ptr = (__u32 *) RAM_BASE;
ptr[0] = 0;
ptr[1] = 1;
ptr[2] = 2;
ptr[3] = 3;
ptr[4] = 4;
ptr[5] = 5;
ptr[6] = 6;
ptr[7] = 7;
while( 1 ) {
ptr = (__u32 *) RAM_BASE;
data[0] = ptr[0] ;
data[1] = ptr[1] ;
data[2] = ptr[2] ;
data[3] = ptr[3] ;
data[4] = ptr[4] ;
data[5] = ptr[5] ;
data[6] = ptr[6] ;
data[7] = ptr[7] ;
for(i=0; i<8; i++) {
debug( "\n\r> [%x] :", i );
debug( "sdram val = %x " , data[i] );
}
if( getcode() != -1 ) break;
}
read back result (incorrect):
> [00000000] :sdram val = 00000001 (should be 00000000)
> [00000001] :sdram val = 00000002 (should be 00000001)
> [00000002] :sdram val = 00000003 (should be 00000002)
> [00000003] :sdram val = 00000000 (should be 00000003)
> [00000004] :sdram val = 00000005 (should be 00000004)
> [00000005] :sdram val = 00000006 (should be 00000005)
> [00000006] :sdram val = 00000007 (should be 00000006)
> [00000007] :sdram val = 00000004 (should be 00000007)
