MC68HC908EY16 Datasheet, PDF (234/278 Pages) Motorola, Inc – Microcontrollers

Development Support
Table 19-1. Monitor Mode Signal Requirements and Options
Mode
Serial
Mode
IRQ
RST
Reset
Vector
Communication
Selection
ICG
PTA0 PTA1 PTB4 PTB3
COP
Communication
Speed
External Bus
Baud
Clock Frequency Rate
Normal
Monitor
V_TST
V_DD
or
V_TST
X
1
0
1
0
OFF Disabled
9.8304
MHz
2.4576
MHz
9600
Forced ^{VDD VDD} $FF
1
Monitor
(blank)
V_SS V_DD
1
0
X
X
OFF Disabled
9.8304
MHz
2.4576
MHz
9600
0
X
X ON Disabled —
Nominal Nominal
1.6 MHz 6300
V_DD V_{DD Not}
User
or or $FF
X
V_SS V_TST
X
X
X CN Enabled
—
Nominal
1.6 MHz
X
MON08
Function
[Pin No.]
V_TST
[6]
RST
[4]
—
COM
[8]
SSEL
[10]
MOD0 MOD1
[12] [14]
—
—
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 9600 except the forced monitor IRQ = V_SS case.
Baud rate using external oscillator is bus frequency / 256.
3. External clock is a 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 PTA0
10 PTA1
12 PTB3
14 PTB4
16 N.C.
19.3.1.2 Forced Monitor Mode
If entering monitor mode without high voltage on IRQ, then all port B pin requirements and conditions are
not in effect. This is to reduce circuit requirements when performing in-circuit programming.
NOTE
If the reset vector is blank and monitor mode is entered, the chip will see an
additional reset cycle after the initial power-on reset (POR). Once the reset
vector has been programmed, the traditional method of applying a voltage,
V_TST, to IRQ must be used to enter monitor mode.
With V_DD on IRQ, an external oscillator of 9.8034 MHz is required for a baud rate of 9600, as the internal
bus frequency is automatically set to the external frequency divided by four.
MC68HC908EY16 • MC68HC908EY8 Data Sheet, Rev. 10
234
Freescale Semiconductor