MC68HC908AS32A Datasheet, PDF (252/280 Pages) Freescale Semiconductor, Inc – Microcontrollers

Development Support
Table 18-1. Mode Selection
Mode
Serial
Mode
Comm.
Selection
IRQ RST
PLL
PTA0 PTC0 PTC1 PTC3
COP
Communication
Speed
External Bus
Baud
Clock Frequency Rate
Comments
V_DD
V_TST or
1
Monitor
V_TST
V_DD
V_TST or
1
V_TST
1
0
0
Off Disabled
4.9152
MHz
2.4576
MHz
9600
PTC3 determines
frequency divider
1
0
1
Off Disabled
4.9152
MHz
1.2288
MHz
4800
V_DD
User or V_DD X
V_SS
X
X
X X Enabled
X
X
X
MON08
Function
[Pin No.]
V_TST
[6]
RST
[4]
COM
[10]
MOD0 MOD1 DIV4
[12] [14] [16]
OSC1
[13]
1. PTA0 must have a pullup resistor to V_DD in monitor mode.
2. Communication speed in the table is an example to obtain a baud rate of 4800 or 9600.
Baud rate using external oscillator is bus frequency / 256.
3. External clock is a 4.9152 MHz crystal on OSC1 and OSC2 or a 4.9152 or 9.8304 MHz canned oscillator on OSC1.
4. X = don’t care
5. MON08 pin refers to P&E Microcomputer Systems’ MON08-Cyclone 2 by 8-pin connector.
NC 1
NC 3
NC 5
NC 7
NC 9
NC 11
OSC1 13
V_DD 15
2 GND
4 RST
6 IRQ
8 NC
10 PTA0
12 PTC0
14 PTC1
16 PTC3
Table 18-2. Mode Differences
Modes
User
Monitor
COP
Enabled
Disabled⁽¹⁾
Reset
Vector High
$FFFE
$FEFE
Reset
Vector Low
$FFFF
$FEFF
Functions
Break
Vector High
$FFFC
$FEFC
Break
Vector Low
$FFFD
$FEFD
SWI
Vector High
$FFFC
$FEFC
SWI
Vector Low
$FFFD
$FEFD
1. If the high voltage (V_TST) is removed from the IRQ pin while in monitor mode, the SIM asserts its COP enable output. The
COP is a mask option enabled or disabled by the COPD bit in the configuration register. See. 19.5 5.0 Volt DC Electrical
Characteristics
MC68HC908AS32A Data Sheet, Rev. 2.0
252
Freescale Semiconductor