RM0385 Datasheet, PDF (1630/1644 Pages) STMicroelectronics – This reference manual targets application developers

Debug support (DBG)
RM0385
40.17.2
TRACE pin assignment
• Asynchronous mode
The asynchronous mode requires 1 extra pin and is available on all packages. It is only
available if using Serial Wire mode (not in JTAG mode).
Table 262. Asynchronous TRACE pin assignment
TPIU pin name
Type
Trace synchronous mode
Description
TRACESWO
O TRACE Async Data Output
• Synchronous mode
The synchronous mode requires from 2 to 6 extra pins depending on the data trace
size and is only available in the larger packages. In addition it is available in JTAG
mode and in Serial Wire mode and provides better bandwidth output capabilities than
asynchronous trace.
Table 263. Synchronous TRACE pin assignment
TPIU pin name
Type
Trace synchronous mode
Description
TRACECK
O
TRACE Clock
TRACED[3:0]
O
TRACE Sync Data Outputs
Can be 1, 2 or 4.
TPIU TRACE pin assignment
By default, these pins are NOT assigned. They can be assigned by setting the
TRACE_CLKINEN and TRACE_MODE bits in the MCU Debug component configuration
register. This configuration has to be done by the debugger host.
In addition, the number of pins to assign depends on the trace configuration (asynchronous
or synchronous).
• Asynchronous mode: 1 extra pin is needed
• Synchronous mode: from 2 to 5 extra pins are needed depending on the size of the
data trace port register (1, 2 or 4):
– TRACECK
– TRACED(0) if port size is configured to 1, 2 or 4
– TRACED(1) if port size is configured to 2 or 4
– TRACED(2) if port size is configured to 4
– TRACED(3) if port size is configured to 4
To assign the TRACE pin, the debugger host must program the bits TRACE_CLKINEN and
TRACE_MODE[1:0] of the Debug MCU configuration register (DBGMCU_CR). By default
the TRACE pins are not assigned.
This register is mapped on the external PPB and is reset by the PORESET (and not by the
SYSTEM reset). It can be written by the debugger under SYSTEM reset.
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