RISC Processors
MSC8144E Reference Manual, Rev. 3
Freescale Semiconductor
18-3
18.2
RISC Processors
The two 32-bit RISC processors reside on a bus separate from the SC3400 cores, and can,
therefore, perform tasks independently from the DSP cores. The RISC processors handle
lower-layer communications tasks and DMA control, freeing the DSP cores to handle
higher-layer activities. The RISC processors work with the UCCs to implement
user-programmable protocols and manage the serial DMA (SDMA) channels that transfer data
between the I/O channels and memory. The RISC processor architecture and instruction set are
optimized for data communications and data processing required by many wire-line and wireless
communications standards. The SC3400 DSP cores issues commands to the RISC processors by
writing to the QUICC Engine Command Register (CECR), which is described in Section 18.10.
The RISC processors execute the commands to ensure synchronization with other tasks running
on the QUICC Engine subsystem. The DSP core sets the CECR[FLG] bit when it issues a
command, and the QUICC Engine subsystem clears the FLG after execution, indicating to the
DSP core that it is ready for the next command. Subsequent commands to the CECR can be given
only after FLG is clear. The software reset command may be issued by setting RST even if the
FLG bit is set. The CECR rarely needs to be accessed. For example, to terminate the transmission
of a frame without waiting until the end, a
STOP
TX
command is issued through the CECR. The
worst-case command execution latency is 200 clocks and the typical command execution latency
is about 40 clocks. The RISC processors give SDMA commands to the SDMA. RISC processor
features include:
One QUICC Engine clock cycle (CLASS128 default, programmable after initialization)
per instruction
32-bit instruction object code
Code execution from internal ROM or RAM
32-bit ALU data path
64-bit multi-port RAM access
Optimized for communications processing
DMA bursting of serial data to/from external memory
18.2.1
SC3400 Core Interface
The RISC processors communicate with the SC3400 cores in several ways:
Many parameters are exchanged through the multi-port RAM.
The RISC processors can execute special commands issued by the SC3400 cores. These
commands should be issued only in special situations such as exceptions or error recovery.
The RISC processor generates interrupts through the interrupt controller.
The SC3400 cores can read the QUICC Engine subsystem status/event registers at any
time.
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 ...