Chapter 20 Debug (S12XDBGV2)
MC9S12XDP512 Data Sheet, Rev. 2.11
Freescale Semiconductor 793

XGATE activity can still be compared, traced and can be used to generate a breakpoint to the XGATE

module. When the CPU enters active BDM mode through a BACKGROUND command, with the DBG

module armed, the DBG remains armed.

The DBG module tracing is disabled if the MCU is secure. Breakpoints can however still be generated if

the MCU is secure.

20.1.4 Block Diagram

Figure 20-1 shows a block diagram of the debug module.

Figure 20-1. Debug Block Diagram
20.2 External Signal Description

The DBG sub-module features two external tag input signals (see Table 20-2). See Device User Guide

(DUG) for the mapping of these signals to device pins. These tag pins may be used for the external tagging

in emulation modes only

Table 20-1. Mode Dependent Restriction Summary
BDM
Enable
BDM
Active
MCU
Secure
Comparator Matches
Enabled
Breakpoints
Possible
Tagging
Possible
Tracing
Possible
x x 1 Yes Yes Yes No
0 0 0 Yes Only SWI Yes Yes
0 1 0 Active BDM not possible when not enabled
1 0 0 Yes Yes Yes Yes
1 1 0 XGATE only XGATE only XGATE only XGATE only
CPU BUS
BUS INTERFACE
TRIGGER
EXTERNAL TAGHI / TAGLO
MATCH0
XGATE BUS
COMPARATOR B
COMPARATOR C
COMPARATOR D
COMPARATOR A
MATCH1
MATCH2
MATCH3
READ TRACE DATA (DBG READ DATA BUS)
SECURE
BREAKPOINT REQUESTS
XGATE S/W BREAKPOINT REQUEST
TAGS
TAGHITS
STATE
CPU & XGATE
COMPARATOR
MATCH CONTROL
TAG &
TRIGGER
CONTROL
LOGIC
STATE
SEQUENCER
TRACE
BUFFER
TRACE
CONTROL
TRIGGER