AN2295 Freescale Semiconductor / Motorola, AN2295 Datasheet - Page 22

• Manufacturer Part Number: AN2295
• Description: Developers Serial Bootloader for M68HC08 and HCS08 MCUs
• Manufacturer: Freescale Semiconductor / Motorola

FC Protocol, Version 2, HC9S08 Implementation
User Code Start
To provide a register setup similar to the way it appears after MCU reset, the user code is started in an
unusual way.
Software Reset
If the bootloader must quit and run user code, an illegal operation is intentionally executed (HCS08 illegal
opcode $8D). This causes an illegal operation reset and the MCU restarts. During bootloader startup, the
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RESET VECTOR (bootloader start)
RELOCATED INTERRUPT VECTOR TABLE
INTERRUPT VECTOR TABLE
RESET VECTOR
INTERRUPT VECTOR 1
INTERRUPT VECTOR 2
INTERRUPT VECTOR 3
INTERRUPT VECTOR 30
INTERRUPT VECTOR 31
original interrupt vector table
is empty (unused)
its content is relocated
Figure 17. Interrupt Vector Table Relocation Explanation (HCS08)
Developer’s Serial Bootloader for M68HC08 and HCS08 MCUs, Rev. 6
...
0XFFFE
0XFFC0
0XFDFE
0XFDEC
0XFDEA
0XFDE8
0XFDC4
0XFDC2
0XFDC0
BOOTLOADER CODE
START
USER CODE
START (RESET)
INTERRUPT ROUTINE 1
INTERRUPT ROUTINE 2
INTERRUPT ROUTINE 30
INTERRUPT ROUTINE 31
Freescale Semiconductor
...
EXIT
0XFFB0
0XFD00