MC68HC908QY4A_10 Datasheet, PDF (148/200 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

Development Support
Table 15-1. Monitor Mode Signal Requirements and Options
Mode
Serial
Communi-
IRQ RST Reset _cation
(PTA2) (PTA3) Vector
Mode
Selection
PTA0 PTA1 PTA4
COP
Communication
Speed
External Bus
Baud
Clock Frequency Rate
Comments
Normal
Monitor
V_TST
V_DD
X
1
1
0
Disabled
9.8304
MHz
2.4576
MHz
9600
Provide external
clock at OSC1.
Forced ^VDD
X
$FFFF
(blank)
1
Monitor
V_SS
X
$FFFF
(blank)
1
X
X
Disabled
9.8304
MHz
2.4576
MHz
9600
Provide external
clock at OSC1.
X
X Disabled X
3.2 MHz
(Trimmed)
9600
Internal clock is
active.
User
X
X
Not
$FFFF
X
X
X Enabled
X
X
X
MON08
Function
[Pin No.]
V_TST
[6]
RST
[4]
—
COM MOD0 MOD1
[8]
[12] [10]
—
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. Baud rate using external oscillator is bus
frequency / 256 and baud rate using internal oscillator is bus frequency / 335.
3. External clock is a 9.8304 MHz oscillator on OSC1.
4. Lowering V_TST once monitor mode is entered allows the clock source to be controlled by the OSCSC register.
5. X = don’t care
6. 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 PTA4
12 PTA1
14 NC
16 NC
15.3.1.1 Normal Monitor Mode
RST and OSC1 functions will be active on the PTA3 and PTA5 pins respectively as long as V_TST is
applied to the IRQ pin. If the IRQ pin is lowered (no longer V_TST) then the chip will still be operating in
monitor mode, but the pin functions will be determined by the settings in the configuration registers (see
Chapter 5 Configuration Register (CONFIG)) when V_TST was lowered. With V_TST lowered, the BIH and
BIL instructions will read the IRQ pin state only if IRQEN is set in the CONFIG2 register.
If monitor mode was entered with V_TST on IRQ, then the COP is disabled as long as V_TST is applied to
IRQ.
15.3.1.2 Forced Monitor Mode
If entering monitor mode without high voltage on IRQ, then startup port pin requirements and conditions,
(PTA1/PTA4) are not in effect. This is to reduce circuit requirements when performing in-circuit
programming.
MC68HC908QYA/QTA Family Data Sheet, Rev. 3
148
Freescale Semiconductor