* sdram init MRS command
@ 2006-12-22 9:34 陈希
0 siblings, 0 replies; only message in thread
From: 陈希 @ 2006-12-22 9:34 UTC (permalink / raw)
To: u-boot-users; +Cc: linuxppc-embedded
Hi,
CPU type: MPC885
SDRAM: 48LC16M16A2-75 x2
memctl->memc_mar= 0x00000088;
memctl->memc_or1 = CFG_OR1_PRELIM;
memctl->memc_br1 = CFG_BR1_PRELIM;
memctl->memc_mamr = CFG_MAMR_9COL & (~(MAMR_PTAE)); /* no
refresh yet */
udelay(200);
memctl->memc_mcr=0x80002105; ->>>>>>>> after this I think the
function should sent data through address line
udelay(1);
memctl->memc_mamr= ( (CFG_MAMR_9COL &0xfffffff0) |0x08);
udelay(200);
As you see, The code set mar and run the ram word 0x05-0x07 to
precharge ,nop and MRS. After run MRS command I think the code should write
data through address line to set mode. But I don't find this step. The
datasheet said mode redister are set through A0-A12. My question is how the
mpc8xx set sdram mode.
Thanks
Andy
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