MC68HC908AP16CFA MOTOROLA [Motorola, Inc], MC68HC908AP16CFA Datasheet - Page 156

• Manufacturer Part Number: MC68HC908AP16CFA
• Description: Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

Monitor ROM (MON)
10.3.1 Entering Monitor Mode
Data Sheet
156
Table 10-1
specified in the table, monitor mode may be entered after a POR and will
allow communication at 9600 baud provided one of the following sets of
conditions is met:
If V
(above condition set 1), the bus frequency is a divide-by-two of the input
clock. If PTB0 is high with V
entry, the bus frequency will be a divide-by-four of the input clock.
Holding the PTB0 pin low when entering monitor mode causes a bypass
of a divide-by-two stage at the oscillator only if V
In this event, the CGMOUT frequency is equal to the CGMXCLK
frequency, and the OSC1 input directly generates internal bus clocks. In
this case, the OSC1 signal must have a 50% duty cycle at maximum bus
frequency.
If entering monitor mode without high voltage on IRQ1 (above condition
set 2 or 3, where applied voltage is either V
requirements and conditions, including the PTB0 frequency divisor
selection, are not in effect. This is to reduce circuit requirements when
performing in-circuit programming.
1. If $FFFE and $FFFF do not contain $FF (programmed state):
2. If $FFFE and $FFFF both contain $FF (erased state):
3. If $FFFE and $FFFF both contain $FF (erased state):
Freescale Semiconductor, Inc.
TST
For More Information On This Product,
– The external clock is 4.9152 MHz with PTB0 low or
– IRQ1 = V
– The external clock is 9.8304 MHz
– IRQ1 = V
– The external clock is 32.768 kHz (crystal)
– IRQ1 = V
is applied to IRQ1 and PTB0 is low upon monitor mode entry
9.8304 MHz with PTB0 high
IRQ1 pullup; PLL off)
32.768 kHz to an internal bus frequency of 2.4576 MHz
shows the pin conditions for entering monitor mode. As
Go to: www.freescale.com
SS
TST
DD
(this setting initiates the PLL to boost the external
(this can be implemented through the internal
(PLL off)
TST
applied to IRQ1 upon monitor mode
MC68HC908AP Family — Rev. 2.5
DD
or V
TST
SS
), then all port A pin
is applied to IRQ1.
MOTOROLA