MM912H634DM1AER2 Freescale Semiconductor, MM912H634DM1AER2 Datasheet - Page 201

• Manufacturer Part Number: MM912H634DM1AER2
• Description: 16-bit Microcontrollers - MCU 64KS12 LIN2XLS/HS ISENSE
• Manufacturer: Freescale Semiconductor

Specifications of MM912H634DM1AER2

• Rohs: yes
• Core: HCS12
• Processor Series: MM912F634
• Data Bus Width: 16 bit
• Maximum Clock Frequency: 20 MHz
• Program Memory Size: 32 KB
• Data Ram Size: 2 KB
• On-chip Adc: Yes
• Operating Supply Voltage: 5.5 V to 18 V
• Operating Temperature Range: - 40 C to + 105 C
• Package / Case: LQFP-48
• Mounting Style: SMD/SMT
• A/d Bit Size: 10 bit
• A/d Channels Available: 15
• Interface Type: SPI
• Maximum Operating Temperature: + 105 C
• Minimum Operating Temperature: - 40 C
• Number Of Programmable I/os: 15
• Number Of Timers: 1
• Program Memory Type: Flash
• Supply Voltage - Max: 18 V
• Supply Voltage - Min: 5.5 V

Functional Description and Application Information
4.30.4.1
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
EEPROM and 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 EEPROM or 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 EEPROM and 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.
4.30.4.2
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 (BDM is enabled and active immediately out of special single-chip
reset):
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.
When BDM is activated while CPU executes code overlapping with BDM firmware space the saved program counter (PC) will be
auto incremented by one from the BDM firmware, no matter what caused the entry into BDM active mode (BGND instruction,
BACKGROUND command or breakpoints). In such a case the PC must be set to the next valid address via a WRITE_PC
command before executing the GO command.
Freescale Semiconductor
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Hardware BACKGROUND command
CPU BGND instruction
Breakpoint force or tag mechanism (This method is provided by the S12S_DBG module)
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.
NOTE
Background Debug Module (S12SBDMV1)
MM912F634
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