RM0090: Reference manual - STMicroelectronics

Debug support (DBG) RM0090
33.17.9 TPIU registers
The TPIU APB registers can be read and written only if the bit TRCENA of the Debug
Exception and Monitor Control Register (DEMCR) is set. Otherwise, the registers are read
as zero (the output of this bit enables the PCLK of the TPIU).
Table 236. Important TPIU registers
Address Register Description
0xE0040004 Current port size
0xE00400F0
0xE0040304
0xE0040300
Selected pin
protocol
Formatter and
flush control
Formatter and
flush status
1397/1416 Doc ID 018909 Rev 3
Allows the trace port size to be selected:
Bit 0: Port size = 1
Bit 1: Port size = 2
Bit 2: Port size = 3, not supported
Bit 3: Port Size = 4
Only 1 bit must be set. By default, the port size is one bit.
(0x00000001)
Allows the Trace Port Protocol to be selected:
Bit1:0=
00: Sync Trace Port Mode
01: Serial Wire Output - manchester (default value)
10: Serial Wire Output - NRZ
11: reserved
Bit 31-9 = always ‘0
Bit 8 = TrigIn = always ‘1 to indicate that triggers are indicated
Bit 7-4 = always 0
Bit 3-2 = always 0
Bit 1 = EnFCont. In Sync Trace mode (Select_Pin_Protocol
register bit1:0=00), this bit is forced to ‘1: the formatter is
automatically enabled in continuous mode. In asynchronous
mode (Select_Pin_Protocol register bit1:0 00), this bit can
be written to activate or not the formatter.
Bit 0 = always 0
The resulting default value is 0x102
Note: In synchronous mode, because the TRACECTL pin is not
mapped outside the chip, the formatter is always enabled in
continuous mode -this way the formatter inserts some control
packets to identify the source of the trace packets).
Not used in Cortex-M4F, always read as 0x00000008