Advance Information MC68HC908MR16/MC68HC908MR32 — Rev. 4.0
188 Monitor ROM (MON) MOTOROLA
Monitor ROM (MON)
10.4.1 Entering Monitor Mode
There are two methods for entering monitor:
• The first is the traditional M68HC08 method where VDD + VHI is
applied to IRQ1 and the mode pins are configured appropriately.
• A second method, intended for in-circuit programming
applications, will force entry into monitor mode without requiring
high voltage on the IRQ1 pin when the reset vector locations of the
FLASH are erased ($FF).
NOTE: For both methods, holding the PTC2 pin low when entering monitor
mode causes a bypass of a divide-by-two stage at the oscillator. The
CGMOUT frequency is equal to the CGMXCLK frequency, and the
OSC1 input directly generates internal bus clocks. In this case, the
OSC1 signal must have a 50 percent duty cycle at maximum bus
frequency.
is a summary of the differences between user mode and mo nitor m ode .
10.4.1.1 Normal Monitor Mode
Table 10-2 shows the pin conditions for entering monitor mode.
Table 10-1. Mode Differences
Modes
Functions
COP Rest
Vector
High
Reset
Vector
Low
Break
Vector
High
Break
Vector
Low
SWI
Vector
High
SWI
Vector
Low
User Enabled $FFFE $FFFF $FFFC $FFFD $FFFC $FFFD
Monitor Disabled(1)
1. If the high voltage (VDD + VHI) is removed from the IRQ1 pin or the RST pin, the SIM as-
serts its COP enable output. The COP is a mask option enabled or disab led by the COPD
bit in the configuration register.
$FEFE $FEFF $FEFC $FEFD $FEFC $FEFD