PXR40RM Datasheet, PDF (1394/1434 Pages) Freescale Semiconductor, Inc – PXR40 Microcontroller

Nexus Development Interface (NDI)
31.17.5.1 Data Trace
This section deals with the data trace mechanism supported by the NXDM and NXFR modules. Data trace
is implemented via data write messaging (DWM) and data read messaging (DRM).
31.17.5.2 Data Trace Messaging (DTM)
NXDM and NXFR data trace messaging is accomplished by snooping the NXDM and NXFR data bus,
and storing the information for qualifying accesses (based on enabled features and matching target
addresses). The NXDM (and NXFR) module traces all data access that meet the selected range and
attributes.
NOTE
Data trace is ONLY performed on DMA or FlexRay accesses to the system
bus.
31.17.5.3 DTM Message Formats
The NXDM (and NXFR) block supports five types of DTM Messages — data write, data read, data write
synchronization, data read synchronization and error messages.
31.17.5.3.1 Data Write and Data Read Messages
The data write and data read messages contain the data write/read value and the address of the write/read
access, relative to the previous data trace message. Data write message and data read message information
is messaged out in the following format:
5
4
3
2
1
DATA
U-ADDR
DSZ
SRC
TCODE (000101 or 000110)
msb 1–64 bits
1–32 bits
3 bits
4 bits
6 bits
lsb
Max length = 109 bits; Min length = 15 bits
Figure 31-54. Data Write/Read Message Format
31.17.5.3.2 DTM Overflow Error Messages
An error message occurs when a new message cannot be queued due to the message queue being full. The
FIFO discards incoming messages until it has completely emptied the queue. After it 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 a data trace message attempts to enter the queue while it is being emptied, the error message
incorporates the data trace only error encoding (00010). If a watchpoint also attempts to be queued while
the FIFO is being emptied, then the error message incorporates error encoding (01000).
Error information is messaged out in the following format:
31-78
PXR40 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor