mc68hc708mp16 Freescale Semiconductor, Inc, mc68hc708mp16 Datasheet - Page 194

• Manufacturer Part Number: mc68hc708mp16
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Monitor ROM (MON)
10.4.1 Entering Monitor Mode
Technical Data
194
NOTE:
Table 10-1
Enter monitor mode by either:
The MCU sends a break signal (10 consecutive logic 0s) to the host
computer, indicating that it is ready to receive a command. The break
signal also provides a timing reference to allow the host to determine the
necessary baud rate.
Monitor mode uses alternate vectors for reset, SWI, and break interrupt.
The alternate vectors are in the $FE page instead of the $FF page and
allow code execution from the internal monitor firmware instead of user
code. The COP module is disabled in monitor mode as long as
V
Section 7. System Integration Module (SIM)
modes of operation.)
Holding the PTC2 pin low when entering monitor mode causes a bypass
of a divide-by-two stage at the oscillator. 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.
V
V
DD
DD
DD
•
•
+ V
+ V
+ V
Executing a software interrupt instruction (SWI) or
Applying a logic 0 and then a logic 1 to the RST pin.
HI
HI
HI
is applied to either the IRQ1/V
shows the pin conditions for entering monitor mode.
1 0 1 1
1 0 1 0
Monitor ROM (MON)
Table 10-1. Mode Selection
Monitor
Monitor
Mode
CGMXCLK
---------------------------- -
2
PP
CGMXCLK
CGMOUT
pin or the RST pin. (See
or
MC68HC708MP16
for more information on
CGMVCLK
---------------------------- -
Freescale Semiconductor
2
Frequency
CGMOUT
------------------------- -
CGMOUT
------------------------- -
—
Bus
Rev. 3.1
2
2