sc9s08mz16 Freescale Semiconductor, Inc, sc9s08mz16 Datasheet - Page 32

• Manufacturer Part Number: sc9s08mz16
• Description: Hcs08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Chapter 3 Modes of Operation
After entering active background mode, the CPU is held in a suspended state waiting for serial background
commands rather than executing instructions from the user’s application program.
Background commands are of two types:
The active background mode is used to program a bootloader or user application program into the flash
program memory before the MCU is operated in run mode for the first time. When the SC9S08MZ16 is
shipped from the Freescale Semiconductor factory, the flash program memory is erased by default unless
specifically noted so there is no program that could be executed in run mode until the flash memory is
initially programmed. The active background mode can also be used to erase and reprogram the flash
memory after it has been previously programmed.
For additional information about the active background mode, refer to
Support.”
3.5
One of two stop modes is entered upon execution of a STOP instruction when the stop mode enable bit
(STOPE) in the system option register is set. In both stop modes, all internal clocks are halted. If the
STOPE bit is not set when the CPU executes a STOP instruction, the MCU does not enter either of the stop
modes and an illegal opcode reset is forced. The stop modes are selected by setting the appropriate bits in
SPMSC2.
The SC9S08MZ16 device does not include stop1 mode.
Table 3-1
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When encountering a DBG breakpoint
Non-intrusive commands, defined as commands that can be issued while the user program is
running. Non-intrusive commands can be issued through the BKGD pin while the MCU is in run
mode; non-intrusive commands can also be executed when the MCU is in the active background
mode. Non-intrusive commands include:
— Memory access commands
— Memory-access-with-status commands
— BDC register access commands
— The BACKGROUND command
Active background commands, which can only be executed while the MCU is in active background
mode. Active background commands include commands to:
— Read or write CPU registers
— Trace one user program instruction at a time
— Leave active background mode to return to the user’s application program (GO)
Stop Modes
summarizes the behavior of the MCU in each of the stop modes.
SC9S08MZ16 MCU Data Sheet, Rev. 0 Draft C
Chapter 12, “Development
Freescale Semiconductor