MC68HC08XL36 Datasheet, PDF (153/362 Pages) Freescale Semiconductor, Inc – HCMOS Microcontroller Unit

Freescale Semiconductor, Inc.
Monitor ROM (MON)
Functional Description
Once out of reset, the MCU waits for the host to send eight security
bytes. (See Security on page 161.) After the receiving security bytes, the
MCU sends a break character (10 consecutive logic 0s) to the host,
indicating that it is ready to receive a command.
In monitor mode, the MCU uses different vectors for reset, SWI, and
break interrupt than those for user mode. 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_DD + V_Hi is
applied to either the IRQ pin or the RST pin.
Table 2 summarizes the differences between user mode and monitor
mode.
Table 2. Mode Differences
Functions
Modes
COP
Reset Reset Break Break SWI SWI
Vector Vector Vector Vector Vector Vector
High Low High Low High Low
User Enabled $FFFE $FFFF $FFFC $FFFD $FFFC $FFFD
Monitor Disabled⁽¹⁾ $FEFE $FEFF $FEFC $FEFD $FEFC $FEFD
1. If the high voltage (V_DD + V_Hi) is removed from the IRQ pin or the RST pin, the COP is
enabled. The COP is a mask option.
5-mon08sp_1p
MOTOROLA
Monitor ROM (MON)
For More Information On This Product,
Go to: www.freescale.com
MC68HC08XL36
153