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11-22
MCF5307 User’s Manual
Synchronous Operation
11.4.3.3 DRAM Controller Mask Registers (DMR0/DMR1)
The DMRn,
Figure 11-17, include mask bits for the base address and for address attributes.
They are the same as in asynchronous operation.
6
IMRS
Initiate mode register set (MRS) command. Setting IMRS generates a MRS command to the
associated SDRAMs. In initialization, IMRS should be set only after all DRAM controller registers are
initialized and PALL and REFRESH commands have been issued. After IMRS is set, the next access to
an SDRAM block programs the SDRAM’s mode register. Thus, the address of the access should be
programmed to place the correct mode information on the SDRAM address pins. Because the
SDRAM does not register this information, it doesn’t matter if the IMRS access is a read or a write or
what, if any, data is put onto the data bus. The DRAM controller clears IMRS after the MRS command
nishes.
0 Take no action
1 Initiate MRS command
5–4
PS
Port size. Indicates the port size of the associated block of SDRAM, which allows for dynamic sizing
of associated SDRAM accesses. PS functions the same in asynchronous operation.
00 32-bit port
01 8-bit port
1x 16-bit port
3
IP
Initiate precharge all (PALL) command. The DRAM controller clears IP after the PALL command is
nished. Accesses via IP should be no wider than the port size programmed in PS.
0 Take no action.
1A PALL command is sent to the associated SDRAM block. During initialization, this command is
executed after all DRAM controller registers are programmed. After IP is set, the next write to an
appropriate SDRAM address generates the PALL command to the SDRAM block.
2
PM
Page mode. Indicates how the associated SDRAM block supports page-mode operation.
0 Page mode on bursts only. The DRAM controller dynamically bursts the transfer if it falls within a
single page and the transfer size exceeds the port size of the SDRAM block. After the burst, the
page closes and a precharge is issued.
1 Continuous page mode. The page stays open and only SCAS needs to be asserted for sequential
SDRAM accesses that hit in the same page, regardless of whether the access is a burst.
1–0
—
Reserved, should be cleared.
31
18 17
9
87654321
0
Field
BAM
—
WP —
C/I AM SC SD UC UD V
Reset
Uninitialized
0
R/W
Addr
MBAR + 0x10C (DMR0), 0x114 (DMR1)
Figure 11-17. DRAM Controller Mask Registers (DMR0 and DMR1)
Table 11-13. DACR0/DACR1 Field Descriptions (Synchronous Mode) (Continued)
Bit
Name
Description
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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