Datasheet
Chapter 7 Debug Module (DBGV1) Block Description
198 MC9S12C-Family / MC9S12GC-Family Freescale Semiconductor
Rev 01.24
7.3.2.1 Debug Control Register 1 (DBGC1)
NOTE
All bits are used in DBG mode only.
NOTE
This register cannot be written if BKP mode is enabled (BKABEN in
DBGC2 is set).
1. The DBG module is designed for backwards compatibility to existing BKP modules. Register and bit names have changed from
the BKP module. This column shows the DBG register name, as well as the BKP register name for reference.
2. Comparator C can be used to enhance the BKP mode by providing a third breakpoint.
Module Base + 0x0020
Starting address location affected by INITRG register setting.
76543210
R
DBGEN ARM TRGSEL BEGIN DBGBRK
0
CAPMOD
W
Reset 0 0 0 00000
= Unimplemented or Reserved
Figure 7-4. Debug Control Register (DBGC1)
Table 7-3. DBGC1 Field Descriptions
Field Description
7
DBGEN
DBG Mode Enable Bit — The DBGEN bit enables the DBG module for use in DBG mode. This bit cannot be
set if the MCU is in secure mode.
0 DBG mode disabled
1 DBG mode enabled
6
ARM
Arm Bit — The ARM bit controls whether the debugger is comparing and storing data in the trace buffer. See
Section 7.4.2.4, “Arming the DBG Module,” for more information.
0 Debugger unarmed
1 Debugger armed
Note: This bit cannot be set if the DBGEN bit is not also being set at the same time. For example, a write of 01
to DBGEN[7:6] will be interpreted as a write of 00.
5
TRGSEL
Trigger Selection Bit — The TRGSEL bit controls the triggering condition for comparators A and B in DBG
mode. It serves essentially the same function as the TAGAB bit in the DBGC2 register does in BKP mode. See
Section 7.4.2.1.2, “Trigger Selection,” for more information. TRGSEL may also determine the type of breakpoint
based on comparator A and B if enabled in DBG mode (DBGBRK = 1). Please refer to Section 7.4.3.1,
“Breakpoint Based on Comparator A and B.”
0 Trigger on any compare address match
1 Trigger before opcode at compare address gets executed (tagged-type)
4
BEGIN
Begin/End Trigger Bit — The BEGIN bit controls whether the trigger begins or ends storing of data in the trace
buffer. See Section 7.4.2.8.1, “Storing with Begin-Trigger,” and Section 7.4.2.8.2, “Storing with End-Trigger,” fo r
more details.
0 Trigger at end of stored data
1 Trigger before storing data