Watchpoint Trace - STMicroelectronics SPC572L series Reference Manual

RM0400
At the moment the previous message is generated, the corresponding MCS fetch trace
buffer may or may not be full. If the buffer is not full, the message is inserted into the buffer
and the fetch trace state machine continues in the running state, otherwise a fetch trace
error message is generated for the corresponding MCS and the fetch trace state machine
goes to the start state.
Note: The MCS is a multi-thread core which executes eight threads, also called channels, in fixed
time-slots of one system clock for each thread. Fetch trace is a per channel resource. Thus
if more than one channel is selected for trace, each one generates its corresponding fetch
trace message. There is one independent fetch state machine and CNT counter for each
selected channel.
42.6.9.2.3 Fetch trace end state
In this state, the fetch trace logic ignores all fetch accesses and waits for the corresponding
MCS trace buffer to be not full. When this happens, a fetch trace end message is inserted
into the buffer with FSCNT equal to CNT (FSCNT = CNT). The CNT value is always reset to
0 when previous state was start state.
If the buffer is always full, the fetch trace logic does not exit end state until a reset occurs.
Note: A Fetch trace end message is sent when a system reset is detected in the GTM module.
There are no further indications about the GTM reset condition.
42.6.10

Watchpoint trace

The GTMDI module provides watchpoint messaging via the auxiliary port, as defined by the
IEEE-ISTO 5001-2002 standard.
42.6.10.1 Messaging
The GTMDI block provides watchpoint messaging using IEEE-ISTO 5001-2002 standard-
defined public messages. When a watchpoint occurs, a watchpoint event is sent to the
Event Queue. If the watchpoint condition occurs while the Event Queue is full, an error
message is generated. The watchpoint message format is shown in
6 bits
TCODE (15)
The values for the WPHIT packet are described in
Notice that WPHIT is never 0 because the message is only generated when a watchpoint
has occurred.
42.7 Initialization/application information
42.7.1 Accessing GTMDI tool-mapped registers
To initialize the JTAG port for register accesses, the following sequence is required:
Figure 465. Watchpoint hit message format
K bits
SRC
Length = 21+Kbits
DocID027809 Rev 4
GTM Development Interface (GTMDI)
Figure
15 bits
WPHIT
Table 508, Table 509
465.
and Table 510.
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