PXR40RM Datasheet, PDF (1360/1434 Pages) Freescale Semiconductor, Inc – PXR40 Microcontroller

Nexus Development Interface (NDI)
31.13.2.6 Program Correlation Messages
Program correlation messages are used to correlate events to the program flow that are not necessarily
associated with the instruction stream. To maintain accurate instruction tracing information when entering
debug mode or a CPU low power mode (where tracing can be disabled), this message is sent upon entry
into one of these two modes and includes the instruction count and branch history. Program correlation is
messaged out in the following format:
5
4
3
2
1
HIST
I-CNT
EVCODE
SRC
msb 1–32 bits
1–8 bits
4 bits
4 bits
Max length = 54 bits; Min length = 16 bits
Figure 31-21. Program Correlation Message Format
TCODE (100001)
6 bits lsb
31.13.2.7 BTM Overflow Error Messages
An error message occurs when a new message cannot be queued because the message queue is full. The
FIFO discards incoming messages until the queue is completely empty. After it is empty, an error message
is queued. The error encoding indicates which message types were denied queueing while the FIFO was
emptying.
If only a program trace message attempts to enter the queue while it is being emptied, the error message
incorporates the program trace only error encoding (00001). If both OTM and program trace messages
attempt to enter the queue, the error message incorporates the OTM and program 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).
NOTE
The OVC bits within the DC1 register can be set to delay the CPU to
alleviate (but not eliminate) potential overrun situations.
Error information is messaged out in the following format:
3
2
1
ECODE (00001 / 00111 / 01000)
SRC
TCODE (001000)
msb
5 bits
4 bits
6 bits lsb
Fixed length = 15 bits
Figure 31-22. Error Message Format
31.13.3 Program Trace Synchronization Messages
A program trace direct/indirect branch with sync message is messaged via the auxiliary port
(provided program trace is enabled) for the following conditions (see Table 31-26):
• Initial program trace message upon the first direct/indirect branch after exit from system reset or
whenever program trace is enabled
31-44
PXR40 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor