Hello,
I am currently using a TQM866 with a cpu clock of 133MHz and I have problems with the configuration of the SDRAM. Here attached there is the sdram_table from the following file:
/u-boot_1.0.0/board/siemens/CCM/ccm.c
#define _NOT_USED_ 0xFFFFFFFF
const uint sdram_table[] = { /* * Single Read. (Offset 0 in UPMA RAM) */ 0x1F0DFC04, 0xEFAFBC04, 0x1EAF7C04, 0xF1AFFC04, 0xEFBAFC00, 0x1FF5FC47, _NOT_USED_, _NOT_USED_, /* last */
/* * Burst Read. (Offset 8 in UPMA RAM) */ 0x1F0DFC04, 0xEFAFBC04, 0x1EAF7C04, 0xF0AFFC04, 0xF0AFFC00, 0xF0AFFC00, 0xF1AFFC00, 0xEFBAFC00, /* last */ 0x1FF5FC47, _NOT_USED_, _NOT_USED_, _NOT_USED_, _NOT_USED_, _NOT_USED_, _NOT_USED_, _NOT_USED_,
/* * Single Write. (Offset 18 in UPMA RAM) */ 0x1F0DFC04, 0xEEABBC00, 0x01B27C04, 0xFFFFFC04, 0x1FF5FC47, _NOT_USED_, _NOT_USED_, _NOT_USED_, /* last */
/* * Burst Write. (Offset 20 in UPMA RAM) */ 0x1F0DFC04, 0xEEABBC00, 0x10A77C00, 0xF0AFFC00, 0xF0AFFC00, 0xE1BAFC04, 0xFFFFFC04, 0x1FF5FC47, /* last */ _NOT_USED_, _NOT_USED_, _NOT_USED_, _NOT_USED_,
/* * SDRAM Initialization (offset 2C in UPMA RAM) * * This is no UPM entry point. The following definition uses * the remaining space to establish an initialization * sequence, which is executed by a RUN command. * */ 0x1FF5FC34, 0xEFEABC34, 0x1FB57C35, _NOT_USED_, /* last */
/* * Refresh (Offset 30 in UPMA RAM) */ 0x1FFD7C84, 0xFFFFFC04, 0xFFFFFC04, 0xFFFFFC04, 0xFFFFFC84, 0xFFFFFC07, _NOT_USED_, _NOT_USED_, /* last */ _NOT_USED_, _NOT_USED_, _NOT_USED_, _NOT_USED_, /* * Exception. (Offset 3c in UPMA RAM) */ 0xFFFFFC07, _NOT_USED_, _NOT_USED_, _NOT_USED_, /* last */ };
We have only the following custom connections:
RAS --> GPL2 A10 --> GPL0 CAS --> GPL3 WE --> GPL1
Freescale said that the SDRAM timing is determined by patterns programmed by the user in the UPM (User Programmable Machine). According to the SDRAM manufacturers specification the "Write Recovery Time" tWR is 15ns minimum. In the current UPM patterns they see only one clock period for tWR. The clock period can be determined as follows: This also explains why the board works ok when the core frequency is reduced to 130MHz, since this translates to a bus clock period of 15.38ns. They asked to insert another clock period in the UPM pattern for "Write Recovery Time".
I would like to know how to modify the table to introduce the modification suggested by Freescale.
Thanks in advance for you support
Agostino Sette