MC68HC908JK1 Datasheet, PDF (107/210 Pages) Motorola, Inc – MC68HC908JK1

Monitor ROM (MON)
Functional Description
Table 9-2 is a summary of the vector differences between user mode
and monitor mode.
Table 9-2. Monitor Mode Vector Differences
Functions
Modes
COP
Reset Reset Break Break SWI
SWI
Vector Vector Vector Vector Vector Vector
High Low High Low High Low
User
Enabled $FFFE $FFFF $FFFC $FFFD $FFFC $FFFD
Monitor Disabled⁽¹⁾ $FEFE $FEFF $FEFC $FEFD $FEFC $FEFD
Notes:
1. If the high voltage (V_DD + V_HI) is removed from the IRQ1 pin or the RST pin, the SIM
asserts its COP enable output. The COP is a mask option enabled or disabled by the
COPD bit in the configuration register.
When the host computer has completed downloading code into the MCU
RAM, the host then sends a RUN command, which executes an RTI,
which sends control to the address on the stack pointer.
9.4.2 Baud Rate
The communication baud rate is dependant on oscillator frequency. The
state of PTB3 also affects baud rate if entry to monitor mode is by
IRQ1 = V_DD + V_HI. When PTB3 is high, the divide by ratio is 1024. If the
PTB3 pin is at logic zero upon entry into monitor mode, the divide by ratio
is 512.
Table 9-3. Monitor Baud Rate Selection
Monitor Mode
Entry By:
IRQ1 = V_DD + V_HI
Blank reset vector,
IRQ1 = V_DD
Input Clock
Frequency
4.9152 MHz
9.8304 MHz
4.9152 MHz
9.8304 MHz
4.9152 MHz
PTB3
0
1
1
X
X
Baud Rate
9600 bps
9600 bps
4800 bps
9600 bps
4800 bps
MC68H(R)C908JL3 — Rev. 1.0
MOTOROLA
Monitor ROM (MON)
Technical Data
107