PXS20RM Datasheet, PDF (1121/1368 Pages) Freescale Semiconductor, Inc – PXS20 Microcontroller

Nexus Crossbar Slave Port Data Trace Module (NXSS) [cut2/3 only]
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:
3
2
1
ECODE (00010 / 01000)
SRC
TCODE (001000)
MSB
5 bits
Fixed length = 15 bits
4 bits
6 bits LSB
Figure 33-12. Error Message Format
33.6.4.3 Data Trace Synchronization Messages
A data trace write/read w/ sync. message is messaged via the auxiliary port (provided data trace is enabled)
for the following conditions (refer to Table 33-12):
• Initial data trace message upon exit from system reset or whenever data trace is enabled is a
synchronization message.
• Upon returning from debug mode, the first data trace message is a synchronization message.
• After occurrence of queue overrun (can be caused by any trace message), the first data trace
message is a synchronization message.
• After the periodic data trace counter has expired indicating 255 without-sync data trace messages
have occurred since the last with-sync message occurred.
• Upon assertion of the Event In (EVTI) pin, the first data trace message is a synchronization
message if the EIC bits of the DC register have enabled this feature.
• Upon data trace write/read after the previous DTM message was lost due to an attempted access to
a secure memory location.
• Upon data trace write/read after the previous DTM message was lost due to a collision entering the
FIFO between the DTM message and any of the following: error message, or watchpoint message.
Data trace synchronization messages provide the full address (without leading zeros) and ensure that
development tools fully synchronize with data trace regularly. Synchronization messages provide a
reference address for subsequent DTMs, in which only the unique portion of the data trace address is
transmitted. The format for data trace write/read w/ sync. messages is as follows:
Freescale Semiconductor
PXS20 Microcontroller Reference Manual, Rev. 1
33-13