MC9S12G FREESCALE [Freescale Semiconductor, Inc], MC9S12G Datasheet - Page 256

• Manufacturer Part Number: MC9S12G
• Description: Ignores external trigger. Performs one conversion sequence and stops.
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Background Debug Module (S12SBDMV1)
7.1.2
BDM is available in all operating modes but must be enabled before firmware commands are executed.
Some systems may have a control bit that allows suspending the function during background debug mode.
7.1.2.1
All of these operations refer to the part in run mode and not being secured. The BDM does not provide
controls to conserve power during run mode.
7.1.2.2
If the device is in secure mode, the operation of the BDM is reduced to a small subset of its regular run
mode operation. Secure operation prevents access to Flash other than allowing erasure. For more
information please see
7.1.2.3
The BDM can be used until stop mode is entered. When CPU is in wait mode all BDM firmware
commands as well as the hardware BACKGROUND command cannot be used and are ignored. In this case
the CPU can not enter BDM active mode, and only hardware read and write commands are available. Also
the CPU can not enter a low power mode (stop or wait) during BDM active mode.
In stop mode the BDM clocks are stopped. When BDM clocks are disabled and stop mode is exited, the
BDM clocks will restart and BDM will have a soft reset (clearing the instruction register, any command in
progress and disable the ACK function). The BDM is now ready to receive a new command.
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This document is valid for the S12G96 and the S12G128 device. All information related to other devices is preliminary.
GO_UNTIL command
Hardware handshake protocol to increase the performance of the serial communication
Active out of reset in special single chip mode
Nine hardware commands using free cycles, if available, for minimal CPU intervention
Hardware commands not requiring active BDM
14 firmware commands execute from the standard BDM firmware lookup table
Software control of BDM operation during wait mode
When secured, hardware commands are allowed to access the register space in special single chip
mode, if the Flash erase tests fail.
Family ID readable from BDM ROM at global address 0x3_FF0F in active BDM
(value for devices with HCS12S core is 0xC2)
BDM hardware commands are operational until system stop mode is entered
Normal modes
General operation of the BDM is available and operates the same in all normal modes.
Special single chip mode
In special single chip mode, background operation is enabled and active out of reset. This allows
programming a system with blank memory.
Modes of Operation
Regular Run Modes
Secure Mode Operation
Low-Power Modes
Section 7.4.1,
MC9S12G Family Reference Manual,
“Security”.
Rev.1.01
Freescale Semiconductor