MC68HC908MR16/MC68HC908MR32 — Rev. 4.0 Advance Information
MOTOROLA Monitor ROM (MON) 189
Monitor ROM (MON)
Functional Description
Table 10-2. Monitor Mode Signal Requirements and Options
IRQ RESET $FFFE
/$FFFF PLL PTC3 PTC4 PTC2 External
Clock(1) CGMOUT Bus
Frequency COP
For Serial
Communication(2) Comment
PTA0 PTA7 Baud
Rate(3) (4)
X GND X X X X X X 0 0 Disabled X X 0 No operation until
reset goes high
VTST
VDD
or
VTST
X OFF100
4.9152
MHz 4.9152
MHz 2.4576
MHz Disabled
1 0 9600 PTC3 and PTC2
voltages only
required if
IRQ = VTST;
PTC2
determines
frequency divider
X 1 DNA
VTST
VDD
or
VTST
X OFF101
9.8304
MHz 4.9152
MHz 2.4576
MHz Disabled
1 0 9600 PTC3 and PTC2
voltages only
required if
IRQ = VTST;
PTC2
determines
frequency divider
X 1 DNA
VDD VDD $FFFF
Blank OFF X X X 9.8304
MHz 4.9152
MHz 2.4576
MHz Disabled
1 0 9600 External frequency
always divided
by 4
X 1 DNA
VDD
or
GND
VTST $FFFF
Blank OFF X X X X Enabled X X
Enters user
mode — will
encounter an
illegal address
reset
VDD
or
GND
VDD
or
VTST
Non-$FF
Programmed OFF X X X X Enabled X X Enters user mode
1. External clock is derived by a 32.768 kHz crystal or a 4.9152/9.8304 MHz off-chip oscillator.
2. DNA = does not apply, X = don’t care
3. PAT0 = 1 if serial communica ti on; PTA0 = X if parallel communi ca tion
4. PTA7 = 0 serial, PTA7 = 1 parallel communication for security code entry