MPC8540 datasheet(384/1302 Pages) FREESCALE

384 / 1302 page

MPC8540 PowerQUICC III Integrated Host Processor Reference Manual, Rev. 1

9-30

Freescale Semiconductor

DDR Memory Controller

Section 9.5.12, “Error Management,” explains how the DDR memory controller handles errors.

9.5.1

DDR SDRAM Interface Operation

The DDR memory controller supports many different DDR SDRAM configurations. SDRAMs

with different sizes can be used in the same system. Fourteen multiplexed address signals and two

logical bank select signals support device densities from 64 Mbit to 1 Gbit. Four chip select (CS)

signals support up to two DIMMs of memory. The DDR SDRAM physical banks can be built from

standard memory modules or directly-attached memory devices. The data path to individual

physical banks is 64 bits wide, 72 bits with ECC. The MPC8540 DDR memory controller supports

physical bank sizes from 32 Mbytes to 1 Gbytes. The physical banks can be constructed using

×8,

×16 memory devices. The memory technologies supported are 64, 128, 256, and 512 Mbit, and

1 Gbit. Nine data qualifier (DQM) signals provide byte selection for memory accesses.

NOTE

An 8-bit DDR SDRAM device has a DQM signal and 8 data signals

(DQ[0:7]). A 16-bit DDR SDRAM device has 2 DQM signals

associated with specific halves of the 16 data signals (DQ[0:7] and

DQ[8:15]).

When ECC is enabled, all memory accesses are performed on double-word boundaries (that is, all

DQM signals are set simultaneously). However, when ECC is disabled, the memory system uses

the DQM signals for byte lane selection.

Table 9-25 shows the DDR memory controller’s relationships between data byte lane 0–7,

MDM[0:7], MDQS[0:7], and MDQ[0:63].

Table 9-25. Byte Lane to Data Relationship

Data Byte Lane Data Bus Mask

Data Bus

Strobe

Data Bus 64-Bit

Mode

0 (MSB)

MDM[0]

MDQS[0]

MDQ[0:7]

MDM[1]

MDQS[1]

MDQ[8:15]

MDM[2]

MDQS[2]

MDQ[16:23]

MDM[3]

MDQS[3]

MDQ[24:31]

MDM[4]

MDQS[4]

MDQ[32:39]

MDM[5]

MDQS[5]

MDQ[40:47]

MDM[6]

MDQS[6]

MDQ[48:55]

7 (LSB)

MDM[7]

MDQS[7]

MDQ[56:63]

MPC8540 Datasheet(PDF) 384 Page - Freescale Semiconductor, Inc

MPC8540 Datasheet(HTML) 384 Page - Freescale Semiconductor, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL