MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1

258 Freescale Semiconductor

Development Support

Table 18-2. Monitor Mode Signal Requirements and Options
IRQ RESET
(S1)
$FFFE
/$FFFF PLL PTC3 PTC4 PTC2
(S2)
External
Clock(1)
1. External clock is derived by a 32.768 kHz crystal or a 4.9152/9.8304 MHz off-chip oscillator.
CGMOUT Bus
Frequency COP
For Serial
Communication(2)
2. DNA = does not apply, X = don’t care
Comment
PTA0 PTA7
(S3)
Baud
Rate(3) (4)
3. PAT0 = 1 if serial communication; PTA0 = X if parallel communication
4. PTA7 = 0 serial, PTA7 = 1 parallel communication for security code entry
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 $FFFF
Blank OFFXXX X —EnabledXX
Enters user mode — will encounter an
illegal address reset
VDD
or
GND
VDD
or
VTST
Non-$FF
Programmed OFF X X X X Enabled X X Enters user mode