Figure 5-2 Dual-Port Ram Dma Interface - ARM ARM966E-S Technical Reference Manual

Direct Memory Access (DMA)
5-4
Figure 5-2 shows how the ARM966E-S DMA port interfaces to a dual-port RAM. For
modelling purposes, the dual-port DMA solution also supports the single-port access
route. Single-port access reduces performance in the dual-port solution and is unlikely
to be used, so to prevent the core from being stalled, DMAWait must be tied LOW.
1
CPU RAM Access 0
SP DMA Access
CPU Read Data
CLK
Copyright © 2000 ARM Limited. All rights reserved.
Table 5-1 Simultaneous access behavior (continued)
Core
access
Read
Write
Write
ARM966E-S
Addr
WriteEnable
Dual Port
ChipSelect
RAM
DataIn
ByteWrite
Port1
Port2
Q1
1
RAMRData1

Figure 5-2 Dual-port RAM DMA interface

DMA
access
Write
Read
Write
DMACLK
DP DMA Access
Q2
RAMRData2
0 SP DMA Access
DMACLK
behavior
Undefined
Undefined
Illegal
DMA Inputs
DMA
Port
DMA Outputs
DMAEnable
ARM DDI 0186A