Datasheet

MC68HC908GZ16 • MC68HC908GZ8 Data Sheet, Rev. 4
Freescale Semiconductor 279
Monitor ROM (MON)
Table 20-1. Monitor Mode Signal Requirements and Options
Mode IRQ RST
Reset
Vector
Serial
Communication
Mode
Selection
Divider
PLL COP
Communication
Speed
Comments
PTA0 PTA1 PTB0 PTB1 PTB4
External
Clock
Bus
Frequency
Baud
Rate
— X GND X X X X X X X X X X X Reset condition
Normal
Monitor
V
TST
V
DD
or
V
TST
X 1 0 1 0 0 OFF Disabled 4 MHz 2 MHz 7200
V
TST
V
DD
or
V
TST
X 1 0 1 0 1 OFF Disabled 8 MHz 2 MHz 7200
Forced
Monitor
V
DD
or
GND
V
DD
$FF
(blank)
1 0 X X X OFF Disabled 8 MHz 2 MHz 7200
User
V
DD
or
GND
V
DD
or
V
TST
Not
$FF X X X X X X Enabled X X X
MON08
Function
[Pin No.]
V
TST
[6]
RST
[4]
—
COM
[8]
SSEL
[10]
MOD0
[12]
MOD1
[14]
DIV4
[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 7200. Baud rate using external oscillator is bus frequency / 278.
3. External clock is an 4.0 MHz or 8.0 MHz crystal on OSC1 and OSC2 or a 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 2 GND
NC 3 4 RST
NC 5 6 IRQ
NC 7 8 PTA0
NC 9 10 PTA1
NC 11 12 PTB0
OSC1 13 14 PTB1
V
DD
15 16 PTB4