Debug support (DBG)
RM0090
1700/1731
DocID018909 Rev 11
38.17.10 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
38.18
DBG register map
The following table summarizes the Debug registers.
.
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
Table 308. Important TPIU registers (continued)
Address
Register
Description
Table 309. DBG register map and reset values
Addr.
Register
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0xE004
2000
DBGMCU
_IDCODE
REV_ID
Reserved
DEV_ID
Reset value
(1)
X X X X X X X X X X X X X X X X
X X X X X X X X X X X X