MC9S08AW8A FREESCALE [Freescale Semiconductor, Inc], MC9S08AW8A Datasheet - Page 35

• Manufacturer Part Number: MC9S08AW8A
• Description: 8-Bit HCS08 Central Processor Unit (CPU)
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Chapter 3
Modes of Operation
3.1
The operating modes of the MC9S08AC16 Series are described in this chapter. Entry into each mode, exit
from each mode, and functionality while in each of the modes are described.
3.2
3.3
This is the normal operating mode for the MC9S08AC16 Series. This mode is selected when the
BKGD/MS pin is high at the rising edge of reset. In this mode, the CPU executes code from internal
memory with execution beginning at the address fetched from memory at 0xFFFE:0xFFFF after reset.
3.4
The active background mode functions are managed through the background debug controller (BDC) in
the HCS08 core. The BDC, together with the on-chip debug module (DBG), provide the means for
analyzing MCU operation during software development.
Active background mode is entered in any of five ways:
Freescale Semiconductor
•
•
•
•
•
•
•
•
Active background mode for code development
Wait mode:
— CPU shuts down to conserve power
— System clocks running
— Full voltage regulation maintained
Stop modes:
— System clocks stopped; voltage regulator in standby
— Stop2 — Partial power down of internal circuits, RAM contents retained
— Stop3 — All internal circuits powered for fast recovery
When the BKGD/MS pin is low at the rising edge of reset
When a BACKGROUND command is received through the BKGD pin
When a BGND instruction is executed
When encountering a BDC breakpoint
When encountering a DBG breakpoint
Introduction
Features
Run Mode
Active Background Mode
MC9S08AC16 Series Data Sheet, Rev. 6
35