MSC8144E Reference Manual, Rev. 3
25-10
Freescale
Semiconductor
Debugging, Profiling, and Performance Monitoring
25.1.5 Enabling the OCE Module
The CHOOSE_ONCE mechanism integrates multiple cores and thus multiple OCE modules on
the same device. Using the CHOOSE_ONCE instruction, you can selectively activate one or
more of the OCE modules on the MSC8144E. The OCE modules selected by the
CHOOSE_ONCE instruction are cascaded as shown in Figure 25-5. Only selected OCE modules
respond to ENABLE_ONCE and DEBUG_REQUEST instructions from the JTAG. All OCE
modules are deselected after reset.
Since all the OCE modules are cascaded, the selection procedure is performed serially. The
sequence is:
1.
Select the CHOOSE_ONCE instruction.
2.
Enter at Shift_DR state the serial stream that specifies the modules to be selected
(1 = selected, 0 = not selected).
The number of bits in this stream, that is, the number of clocks in this state, is equal to the number
of selected SC3400 cores in the cascade, which is four. This state is indicated by the
CHOOSE_CLOCK_DR
signal. For example, for the four SC3400 cores on the MSC8144E, to
activate the fourth core in the cascade, which is the closest to
TDO
and the farthest from
TDI
, the
data is 1,0,0,0 (first a one, then three zeros). If the data is 1,0,1,0, then both the second and the
fourth cells are selected.
Only the OCE command register (ECR) should be accessed in cascaded mode. To do this, first
enter the CHOOSE_ONCE instruction and set ENABLE_ONCE to 1 for all cores. Then shift in
the cascaded value for all ECRs in series. When the shift is ended and the controller issues a
SHIFT_UPDATE, all registers are updated in parallel. However, it is not guaranteed that this
occurs in the same SC3400 clock cycle for all cores.
Figure 25-5. Cascading Multiple OCE Modules
CHOOSE
TDI
Controls
JTAG
Core 0
to TDO
OCE Module
SC3400
SC3400
CHOOSE
Core 3
OCE Module
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 ...