Table 307. Flexible Trace Pin Assignment; Tpui Formatter - STMicroelectronics STM32F405 Reference Manual

RM0090
DBGMCU_CR
register
TRACE
assigned for:
TRACE
_MODE
_IOEN
[1:0]
No Trace
0 XX
(default state)
Asynchronous
1 00
Synchronous
1 01
Trace 1 bit
Synchronous
1 10
Trace 2 bit
Synchronous
1 11
Trace 4 bit
1. When Serial Wire mode is used, it is released. But when JTAG is used, it is assigned to JTDO.
Note: By default, the TRACECLKIN input clock of the TPIU is tied to GND. It is assigned to HCLK
two clock cycles after the bit TRACE_IOEN has been set.
The debugger must then program the Trace Mode by writing the PROTOCOL[1:0] bits in the
SPP_R (Selected Pin Protocol) register of the TPIU.
• PROTOCOL=00: Trace Port Mode (synchronous)
•
PROTOCOL=01 or 10: Serial Wire (Manchester or NRZ) Mode (asynchronous mode).
Default state is 01
It then also configures the TRACE port size by writing the bits [3:0] in the CPSPS_R
(Current Sync Port Size Register) of the TPIU:
•
0x1 for 1 pin (default state)
•
0x2 for 2 pins
•
0x8 for 4 pins
38.17.3

TPUI formatter

The formatter protocol outputs data in 16-byte frames:
•
seven bytes of data
•
eight bytes of mixed-use bytes consisting of:
–
–
•
one byte of auxiliary bits where each bit corresponds to one of the eight mixed-use
bytes:
–
–

Table 307. Flexible TRACE pin assignment

Pins
PB3 /JTDO/
TRACESWO
(1)
Released
TRACESWO
Trace
(1)
Released
1 bit (LSB) to indicate it is a DATA byte ('0) or an ID byte ('1).
7 bits (MSB) which can be data or change of source ID trace.
if the corresponding byte was a data, this bit gives bit0 of the data.
if the corresponding byte was an ID change, this bit indicates when that ID change
takes effect.
DocID018909 Rev 11
TRACE IO pin assigned
PE2/
PE3 /
TRACED[0]
TRACECK
- -
TRACECK TRACED[0]
TRACECK TRACED[0] TRACED[1]
TRACECK TRACED[0] TRACED[1] TRACED[2] TRACED[3]
Debug support (DBG)
PE4 / PE5 /
TRACED[1] TRACED[2]
-
Released
(usable as GPIO)
- -
-
PE6 /
TRACED[3]
-
-
1697/1731
1701