Channels
MSC8144E Reference Manual, Rev. 3
Freescale Semiconductor
26-21
The channel can generate two types of done notification signals when it completes
operation on a descriptor—an interrupt and/or a writeback of the descriptor header.
If selected, the done notification is performed at the end of processing either for every
descriptor or selected descriptors.
If enabled, the channel may also write back status information from the EU(s) involved in
processing the descriptor.
Note:
The done and status writebacks are not performed if the EU(s) generate any error
during processing.
26.3.1 Channel Registers and Structures
Each channel has its own set of registers and structures used for configuration, control, and data
manipulation including the following:
Channel Configuration Register (CCR). Configures the basic channel operation including
burst size, extended addressing, and notification type. It also provides control functions
such as continuing the operation, resetting the channel, writing back status and DONE,
and using an Integrity Check Value (ICV). For details, see Section 26.5.5.1, Channel
Configuration Registers for Channels 1–4 (CCR[1–4]), on page 26-89.
Channel Pointer Status Register (CPSR). Contains status fields and counters to report the
current status of descriptor processing including the G_STATE (gather) and S_STATE
(scatter) fields that report gather and scatter state machine status. For details, see Section
26.5.5.2, Channel Pointer Status Registers (CPSR[1–4]), on page 26-92.
Current Descriptor Pointer Register (CDPR). Contains the address for the currently
processing descriptor. For details, see Section 26.5.5.3, Current Descriptor Pointer
Register (CDPR), on page 26-98.
Channel Fetch FIFO (FF). Each channel contains a Fetch FIFO to store a queue of pointers
to descriptors to process. In a typical operation, the core processor creates a descriptor in
memory containing all relevant mode and location information for the SEC and then
launches the descriptor by writing its address to the SEC Fetch FIFO. The Fetch FIFO can
hold up to 24 descriptor pointers at a time. When the channel reaches the end of the
current descriptor, the next location in the Fetch FIFO is read to launch the next descriptor.
The Fetch Address is written into the FIFO only if the write includes the least significant
byte (bits 7–0). If the Extend Address Enable (EAE) bit is set, then the Extended Fetch
Address must be written before or concurrently with the Fetch Address. Specifying a fetch
address of 0 causes the channel to generate an error and stop. For details, see Section
26.5.5.4, Channel Fetch FIFO (CFF), on page 26-99.
Channel Descriptor Buffer (DB). As with any descriptor used by the SEC, the DB consists
of an 8-byte header and seven 8-byte pointers. This structure is read-only because the
descriptor is always fetched from system memory. For details, see Section 26.5.5.5,
Channel Descriptor Buffer (DB), on page 26-100.
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 ...