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MPC8540 Application Examples

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

Freescale Semiconductor

1-21

address are based on the programmed destination of the transaction. The following is a general

overview of how the ATMUs process transactions over the on-chip fabric. (Refer to Figure 1-2.)

1. When a transaction on one of the fabric ports begins, the ATMU on the origination port

translates the programmed destination address into both a destination fabric port ID and a

local device address.

2. The data is then processed across the on-chip fabric from the origination port to the

destination port.

3. If the destination port connects off-chip (for example, to a PCI or RapidIO device), the

local device address is translated by the destination port ATMU to an outbound address

with respect to the destination port’s memory map, and the data is processed accordingly.

Figure 1-2. Processing Transactions Across the On-Chip Fabric

1.3.20 Data Processing with the e500 Coherency Module

Processing through the ECM is similar to processing across the on-chip fabric (in the sense of how

data is received and transmitted) with the exception that the transaction passes through the ECM.

The purpose of the ECM is to provide a means for any I/O transaction to maintain coherency with

the cacheable DDR SDRAM and the local bus memory. However, simply using the ECM does not

make transactions across it coherent. The e500 and L2 cache are snooped to maintain coherency

only if the transaction across the ECM is designated as global (GBL bit set). Otherwise, the

transaction passes through the ECM using the ECM as a simple conduit to get to its destination.

In essence, only global transactions across the ECM are coherent transactions; all other

transactions (across the on-chip fabric) are non-coherent.

1.4

MPC8540 Application Examples

The following section provides block diagrams of different MPC8540 applications. The MPC8540

is a very flexible device and can be configured to meet many system application needs. In order to

build a system, many factors should be considered.

1.4.1

MPC8540 Applications

The MPC8540 can be used for control processing in applications such as routers, switches,

network memory, internet access devices, storage systems, and image display systems (IADs).

Figure 1-3 shows an MPC8540 as a control plane processor in a high-performance communication

system using symmetric multiprocessing (SMP).

ATMU

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