Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
537
System Controller (SC) and Internal Bus Bridge—Intel
®
81341 and 81342
6.0
System Controller (SC) and Internal Bus Bridge
This chapter describes the System Controllers (SC) of the Intel
®
81341 and 81342 I/O
Processors (81341 and 81342). The System Controller controls the internal bus and its
agents. There are two System Controllers on 81341 and 81342 since there are two
internal busses.
6.1
Overview
The System Controller controls the internal bus agents arbitrating for the internal bus.
The Internal Bus on 81341 and 81342 contains a separate address bus arbiter and data
bus arbiter as the address and data busses are completely de-multiplexed. There are
two internal busses on 81341 and 81342 and therefore there are two system
controllers implemented — one for the North Internal Bus and one for the South
Internal Bus.
• The north internal bus SC controls the two Intel XScale
®
processors, the DDR
Memory Controller, the Bridge, and the SAS Interface.
• The south internal bus SC controls the ATU-E, ATU-X, the Bridge, the DDR SDRAM
Memory Controller, the Application DMAs, the PBI, and the APB interface.
In addition to providing the address bus and data bus arbitration functionality, the SC
also initiates address and data transactions once the bus has been granted. The SC is
also the central hub which takes as inputs all the agents address and data busses, and
then controlling how the address bus or data bus is routed to an agent.
The SC also provides hardware functionality that can be used to force address and data
parity errors. This feature allows software to test error handling routines by forcing
address or data parity error.