mc68hc908gr8vp Freescale Semiconductor, Inc, mc68hc908gr8vp Datasheet - Page 135

• Manufacturer Part Number: mc68hc908gr8vp
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

In monitor mode, the MCU uses different vectors for reset, SWI (software interrupt), and break interrupt
than those for user mode. The alternate vectors are in the $FE page instead of the $FF page and allow
code execution from the internal monitor firmware instead of user code.
Table 15-2
Freescale Semiconductor
summarizes the differences between user mode and monitor mode.
Exiting monitor mode after it has been initiated by having a blank reset
vector requires a power-on reset. Pulling RST low will not exit monitor mode
in this situation.
Monitor
Modes
User
Figure 15-2. Low-Voltage Monitor Mode Entry Flowchart
MC68HC908GR8 • MC68HC908GR4 Data Sheet, Rev. 7
Vector
$FFFE
$FEFE
Reset
High
Table 15-2. Mode Differences
MONITOR MODE
TRIGGERED?
POR RESET
IS VECTOR
EXECUTE
MONITOR
BLANK?
Vector
CODE
$FFFF
$FEFF
Reset
POR
Low
YES
YES
NOTE
NO
NO
$FEFC
Vector
$FFFC
Break
High
Functions
NORMAL USER
Vector
$FFFD
$FEFD
Break
Low
MODE
$FEFC
Vector
$FFFC
High
SWI
Vector
$FFFD
$FEFD
Functional Description
Low
SWI
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