Architecture Overview
MSC8144E Reference Manual, Rev. 3
Freescale Semiconductor
26-3
26.1.2 Controller
The controller manages internal device resources, including the individual execution units (EUs),
FIFOs, the master and slave interfaces to the device system bus, and the internal buses that
connect all the various modules. The controller receives service requests from the core processor
via the slave interface and from the channels and schedules the required activities.
26.1.2.1 Controller Operation
The controller can interface with the execution units in two ways:
Channel-controlled access—A channel can request a particular service from any available
execution unit. This is the normal operating mode.
Core processor-controlled access—The core processor can move data into and out of any
execution unit directly through memory-mapped EU registers. Typically, this is only used
for debug.
The system bus interface and access to system memory are critical factors in performance, and
the 64-bit master and slave interfaces of the SEC controller allows it to achieve performance
unattainable on secondary buses.
26.1.2.1.1 Channel-Controlled Access
Processing begins when a descriptor pointer is written to the Fetch FIFO of one of the channels.
Based on the services requested by the descriptor header, the channel asks the controller to assign
the necessary EUs to that channel. If all appropriate EUs are already reserved by other channels,
the channel stalls and waits to fetch data until an appropriate EU is available. If multiple channels
simultaneously request the same EU, the EU is assigned on a weighted priority or round-robin
basis.
Once the required EU has been reserved, the channel requests that the controller fetch and load
the appropriate data. The controller acts as a master on the system bus, reading and writing on
byte boundaries. The channel operates the EU, and makes further requests to the controller to
write output data to system memory. When the descriptor processing is complete, the channel
asks the controller to release the EU for use by other channels.
26.1.2.1.2 Core Processor-Controlled Access
All execution units (EUs) are memory-mapped, and can be used entirely through register
read/write access. The SEC operates as a slave, and the core processor must write the information
normally provided through the descriptor into the appropriate registers and FIFOs of the SEC.
This method is more processor intensive and requires a great deal of familiarity with the SEC
registers. It is recommended that core processor-controlled access be used only for operations
using a single EU and for debug purposes.
Summary of Contents for MSC8144E
Page 1: ...MSC8144E Reference Manual Quad Core Media Signal Processor MSC8144ERM Rev 3 July 2009 ...
Page 48: ...MSC8144E Reference Manual Rev 3 xlviii Freescale Semiconductor ...
Page 86: ...MSC8144E Reference Manual Rev 3 1 38 Freescale Semiconductor Overview ...
Page 168: ...MSC8144E Reference Manual Rev 3 3 60 Freescale Semiconductor External Signals ...
Page 242: ...MSC8144E Reference Manual Rev 3 5 26 Freescale Semiconductor Reset ...
Page 314: ...MSC8144E Reference Manual Rev 3 8 24 Freescale Semiconductor General Configuration Registers ...
Page 414: ...MSC8144E Reference Manual Rev 3 10 14 Freescale Semiconductor MSC8144E SC3400 DSP Subsystem ...
Page 452: ...MSC8144E Reference Manual Rev 3 11 38 Freescale Semiconductor Internal Memory Subsystem ...
Page 520: ...MSC8144E Reference Manual Rev 3 12 68 Freescale Semiconductor DDR SDRAM Memory Controller ...
Page 1070: ...MSC8144E Reference Manual Rev 3 21 28 Freescale Semiconductor Timers ...