mc9s08qd4 Freescale Semiconductor, Inc, mc9s08qd4 Datasheet - Page 27

• Manufacturer Part Number: mc9s08qd4
• Description: Hcs08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Chapter 3
Modes of Operation
3.1
The operating modes of the MC9S08QD4 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 MC9S08QD4 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 provides the means for analyzing MCU operation during software
development.
Active background mode is entered in any of five ways:
Freescale Semiconductor
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Active background mode for code development
Wait mode:
— CPU shuts down to conserve power
— System clocks running
— Full voltage regulation maintained
Stop modes:
— CPU and bus clocks stopped
— 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
Introduction
Features
Run Mode
Active Background Mode
MC9S08QD4 Series MCU Data Sheet, Rev. 3
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