sc9s12hy64j0vllr Freescale Semiconductor, Inc, sc9s12hy64j0vllr Datasheet - Page 167

• Manufacturer Part Number: sc9s12hy64j0vllr
• Description: S12 Microcontrollers Mcu 16-bit Hcs12 Cisc 32kb Flash 5v Tray
• Manufacturer: Freescale Semiconductor, Inc

“Security”). Firmware commands can only be executed when the system is not secure and is in active
background debug mode (BDM).
5.4.1
If the user resets into special single chip mode with the system secured, a secured mode BDM firmware
lookup table is brought into the map overlapping a portion of the standard BDM firmware lookup table.
The secure BDM firmware verifies that the on-chip Flash EEPROM are erased. This being the case, the
UNSEC and ENBDM bit will get set. The BDM program jumps to the start of the standard BDM firmware
and the secured mode BDM firmware is turned off and all BDM commands are allowed. If the Flash do
not verify as erased, the BDM firmware sets the ENBDM bit, without asserting UNSEC, and the firmware
enters a loop. This causes the BDM hardware commands to become enabled, but does not enable the
firmware commands. This allows the BDM hardware to be used to erase the Flash.
BDM operation is not possible in any other mode than special single chip mode when the device is secured.
The device can only be unsecured via BDM serial interface in special single chip mode. For more
information regarding security, please see the S12S_9SEC Block Guide.
5.4.2
The system must be in active BDM to execute standard BDM firmware commands. BDM can be activated
only after being enabled. BDM is enabled by setting the ENBDM bit in the BDM status (BDMSTS)
register. The ENBDM bit is set by writing to the BDM status (BDMSTS) register, via the single-wire
interface, using a hardware command such as WRITE_BD_BYTE.
After being enabled, BDM is activated by one of the following
When BDM is activated, the CPU finishes executing the current instruction and then begins executing the
firmware in the standard BDM firmware lookup table. When BDM is activated by a breakpoint, the type
of breakpoint used determines if BDM becomes active before or after execution of the next instruction.
In active BDM, the BDM registers and standard BDM firmware lookup table are mapped to addresses
0x3_FF00 to 0x3_FFFF. BDM registers are mapped to addresses 0x3_FF00 to 0x3_FF0B. The BDM uses
these registers which are readable anytime by the BDM. However, these registers are not readable by user
programs.
1. BDM is enabled and active immediately out of special single-chip reset.
2. This method is provided by the S12S_DBG module.
Freescale Semiconductor
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Hardware BACKGROUND command
CPU BGND instruction
Breakpoint force or tag mechanism
Security
Enabling and Activating BDM
If an attempt is made to activate BDM before being enabled, the CPU
resumes normal instruction execution after a brief delay. If BDM is not
enabled, any hardware BACKGROUND commands issued are ignored by
the BDM and the CPU is not delayed.
MC9S12HY/HA-Family Reference Manual, Rev. 1.04
2
NOTE
1
:
Background Debug Module (S12SBDMV1)
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