S912XEG128J2MAA Datasheet, PDF (310/1324 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 8 S12X Debug (S12XDBGV3) Module
8.3.2 Register Descriptions
This section consists of the S12XDBG control and trace buffer register descriptions in address order. Each
comparator has a bank of registers that are visible through an 8-byte window between 0x0028 and 0x002F
in the S12XDBG module register address map. When ARM is set in DBGC1, the only bits in the
S12XDBG module registers that can be written are ARM, TRIG, and COMRV[1:0].
8.3.2.1 Debug Control Register 1 (DBGC1)
Address: 0x0020
R
W
Reset
7
ARM
0
6
0
TRIG
0
5
XGSBPE
0
4
BDM
0
3
2
DBGBRK
0
0
1
0
COMRV
0
0
Figure 8-3. Debug Control Register (DBGC1)
Read: Anytime
Write: Bits 7, 1, 0 anytime
Bit 6 can be written anytime but always reads back as 0.
Bits 5:2 anytime S12XDBG is not armed.
NOTE
If a write access to DBGC1 with the ARM bit position set occurs
simultaneously to a hardware disarm from an internal trigger event, then the
ARM bit is cleared due to the hardware disarm.
NOTE
When disarming the S12XDBG by clearing ARM with software, the
contents of bits[5:2] are not affected by the write, since up until the write
operation, ARM = 1 preventing these bits from being written. These bits
must be cleared using a second write if required.
Field
7
ARM
6
TRIG
Table 8-5. DBGC1 Field Descriptions
Description
Arm Bit — The ARM bit controls whether the S12XDBG module is armed. This bit can be set and cleared by
user software and is automatically cleared on completion of a tracing session, or if a breakpoint is generated with
tracing not enabled. On setting this bit the state sequencer enters State1.
0 Debugger disarmed
1 Debugger armed
Immediate Trigger Request Bit — This bit when written to 1 requests an immediate trigger independent of
comparator or external tag signal status. When tracing is complete a forced breakpoint may be generated
depending upon DBGBRK and BDM bit settings. This bit always reads back a 0. Writing a 0 to this bit has no
effect. If TSOURCE are clear no tracing is carried out. If tracing has already commenced using BEGIN- or MID
trigger alignment, it continues until the end of the tracing session as defined by the TALIGN bit settings, thus
TRIG has no affect. In secure mode tracing is disabled and writing to this bit has no effect.
0 Do not trigger until the state sequencer enters the Final State.
1 Trigger immediately .
MC9S12XE-Family Reference Manual Rev. 1.25
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