Nexus
MPC5566 Microcontroller Reference Manual, Rev. 2
25-46 Freescale Semiconductor
2. The second pass through the DR then shifts the data in or out of the JTAG port, lsb first.
a) During a read access, data is latched from the selected Nexus register when the JTAG state
machine passes through the capture-DR state.
b) During a write access, data is latched into the selected Nexus register when the JTAG state
machine passes through the update-DR state.
25.12 Ownership Trace
This section details the ownership trace features of the NZ6C3 module.
Ownership trace provides a macroscopic view, such as task flow reconstruction, when debugging software
written in a high level (or object-oriented) language. It offers the highest level of abstraction for tracking
operating system software execution. This is especially useful when the developer is not interested in
debugging at lower levels.
25.12.1 Ownership Trace Messaging (OTM)
Ownership trace information is messaged via the auxiliary port using an ownership trace message (OTM).
The e200z6 processor contains a Power Architecture Book E defined process ID register within the CPU.
The process ID register is updated by the operating system software to provide task/process ID
information. The contents of this register are replicated on the pins of the processor and connected to
Nexus. The process ID register value can be accessed using the mfspr/mtspr instructions. Please refer to
the e200z6 PowerPC
TM
Core Reference Manualfor more details on the process ID register.
The only condition that causes an ownership trace message occurs when the OTR register is updated or
process ID register by the e200z6 processor, the data is latched within Nexus, and is messaged out via the
auxiliary port, allowing development tools to trace ownership flow.
Ownership trace information is messaged out in the following format:
Figure 25-27. Ownership Trace Message Format
Nexus Register Index: Selected from values in Table 25-24
Read/Write (R/W): 0 Read
1Write
PROCESS
MSB LSB
12
SRC TCODE (000010)
3
6 bits4 bits32 bits
Fixed length = 42 bits
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