mc9s08qg8 Freescale Semiconductor, Inc, mc9s08qg8 Datasheet - Page 244

• Manufacturer Part Number: mc9s08qg8
• Description: Hcs08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Development Support
17.2
Features of the background debug controller (BDC) include:
17.3
All MCUs in the HCS08 Family contain a single-wire background debug interface that supports in-circuit
programming of on-chip nonvolatile memory and sophisticated non-intrusive debug capabilities. Unlike
debug interfaces on earlier 8-bit MCUs, this system does not interfere with normal application resources.
It does not use any user memory or locations in the memory map and does not share any on-chip
peripherals.
BDC commands are divided into two groups:
Typically, a relatively simple interface pod is used to translate commands from a host computer into
commands for the custom serial interface to the single-wire background debug system. Depending on the
development tool vendor, this interface pod may use a standard RS-232 serial port, a parallel printer port,
or some other type of communications such as a universal serial bus (USB) to communicate between the
host PC and the pod. The pod typically connects to the target system with ground, the BKGD pin, RESET,
and sometimes V
which is useful to regain control of a lost target system or to control startup of a target system before the
on-chip nonvolatile memory has been programmed. Sometimes V
power from the target system to avoid the need for a separate power supply. However, if the pod is powered
separately, it can be connected to a running target system without forcing a target system reset or otherwise
disturbing the running application program.
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Single pin for mode selection and background communications
BDC registers are not located in the memory map
SYNC command to determine target communications rate
Non-intrusive commands for memory access
Active background mode commands for CPU register access
GO and TRACE1 commands
BACKGROUND command can wake CPU from stop or wait modes
One hardware address breakpoint built into BDC
Oscillator runs in stop mode, if BDC enabled
COP watchdog disabled while in active background mode
Active background mode commands require that the target MCU is in active background mode (the
user program is not running). Active background mode commands allow the CPU registers to be
read or written, and allow the user to trace one user instruction at a time, or GO to the user program
from active background mode.
Non-intrusive commands can be executed at any time even while the user’s program is running.
Non-intrusive commands allow a user to read or write MCU memory locations or access status and
control registers within the background debug controller.
Features
Background Debug Controller (BDC)
DD
. An open-drain connection to reset allows the host to force a target system reset,
MC9S08QG8 and MC9S08QG4 Data Sheet, Rev. 1.01
DD
can be used to allow the pod to use
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