Freescale Semiconductor e200z3 Reference Manual page 390

Nexus3/Nexus2+ Module
Ownership trace information is messaged out in the format shown in
10.6.3 OTM Error Messages
An error message occurs when the message queue is full and a new message cannot be queued. The FIFO
discards incoming messages until it has completely emptied the queue. Once the queue is emptied, an error
message is queued. The error encoding indicates which types of messages attempted to be queued while
the FIFO was being emptied.
If only an OTM message attempts to enter the queue while the queue is being emptied, the error message
only incorporates the OTM error encoding 00000. If both OTM and either BTM or DTM (that is, OTM
and BTM or OTM and DTM) messages attempt to enter the queue, the error message incorporates the
OTM and program or data trace error encoding 00111. If a watchpoint also attempts to be queued while
the FIFO is being emptied, then the error message incorporates error encoding 01000.
DC1[OVC] can be set to delay the CPU in order to alleviate, but not
eliminate, potential overrun situations.
Error information is messaged out in the format shown in
Error Code (00000, 00111, or 01000)
10.6.4 OTM Flow
Ownership trace messages are generated when the operating system writes to the e200z3 process ID
register (PID0) or the memory-mapped ownership trace register (OTR).
The following flow describes the OTM process:
• The process ID register is a system control register. It is internal to the core processor and can be
accessed by using PPC instructions. The contents of this register are replicated on the pins of the
processor and connected to Nexus.
• Writes to the e200z3 internal process ID register will pulse a write signal to Nexus. The data value
written into the process ID register is latched and formed into the ownership trace message that is
queued to be transmitted.
• Process ID register reads do not cause ownership trace messages to be transmitted by the Nexus 3
module.
10-24
(32 bits)
Task/Process ID Tag
Fixed Length = 42 bits
Figure 10-16. Ownership Trace Message Format
(5 bits)
Source Process
Fixed Length = 15 bits
Figure 10-17. Error Message Format
e200z3 Power Architecture Core Reference Manual, Rev. 2
Figure
Source Process
NOTE
Figure 10-17.
(4 bits)
TCODE (001000)
10-16.
(4 bits) (6 bits)
TCODE (000010)
(6 its)
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