Infineon Technologies TC1796, Руководство пользователя

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TC1796
System Units (Vol. 1 of 2)
Direct Memory Access Controller
User’s Manual 12-21 V2.0, 2007-07
DMA, V2.0
12.1.6 Bus Switch
The Bus Switch of the DMA controller provides the connection from the two DMA Sub-
Blocks to the two FPI Bus interfaces (connected to System Peripheral Bus and Remote
Peripheral Bus) and the MLI bus interface (see
Figure 12-14 ).
A very simple bus bridge is implemented in the Bus Switch. It behaves as a feed-through
for the slave interface on the FPI Bus interface 0 to the other bus interfaces (FPI Bus
interface 1, MLI interface) because the working frequencies are identical on all these
buses. The bridge is the only slave interface in the DMA because all the other interfaces
are master on their buses. The slave interface also provides the access to the DMA and
MLI registers.
The bridge functionality is covered independently from the DMA Move Engines. An
access requesting from the FPI Bus interface 0 (SPB) to locations on the FPI Bus
interface 1 (RPB) has priority over DMA actions. The DMA Move Engines are not
involved in bridge transfers.
Figure 12-14 Bus Switch
One access can be buffered in the bus interfaces.
Note: The accesses of the DMA Move Engine’s bus interfaces to FPI Bus interface 0
and FPI Bus interface 1 are always done in supervisor mode.
ML
I
In
ter
face
MCA05693
Move
Engine 1
DMA Sub-Block 1
Move
Engine 0
DMA Sub-Block 0
Buffer
Bus Switch
M
FPI Bus
Interface 1
Buffer
M/S
FPI Bus
Interface 0
System Peripheral Bus Remote Peripheral Bus
Memory
Checker
MLI0
MLI1
Arbiter/
Switch
Control