RM0390 Rev 4 1315/1328
RM0390 Debug support (DBG)
1318
33.17.10 Example of configuration
• Set the bit TRCENA in the Debug Exception and Monitor Control Register (DEMCR)
• Write the TPIU Current Port Size Register to the desired value (default is 0x1 for a 1-bit
port size)
• Write TPIU Formatter and Flush Control Register to 0x102 (default value)
• Write the TPIU Select Pin Protocol to select the sync or async mode. Example: 0x2 for
async NRZ mode (UART like)
• Write the DBGMCU control register to 0x20 (bit IO_TRACEN) to assign TRACE I/Os
for async mode. A TPIU Sync packet is emitted at this time (FF_FF_FF_7F)
• Configure the ITM and write the ITM Stimulus register to output a value
Table 252. Important TPIU registers
Address Register Description
0xE0040004 Current port size
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)
0xE00400F0 Selected pin protocol
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
0xE0040304
Formatter and flush
control
Bits 31-9 = always ‘0
Bit 8 = TrigIn = always ‘1 to indicate that triggers are indicated
Bits 7-4 = always 0
Bits 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).
0xE0040300
Formatter and flush
status
Not used in Cortex
®
-M4 with FPU, always read as 0x00000008