mc68hc912dg128 Freescale Semiconductor, Inc, mc68hc912dg128 Datasheet - Page 365

• Manufacturer Part Number: mc68hc912dg128
• Description: M68hc12 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

18.4.4.1 Enabling BDM lockout
18.4.4.2 Disabling BDM lockout
MC68HC912DG128 — Rev 3.0
MOTOROLA
NOTE:
Enabling the BDM lockout feature is only possible in special modes
(SMODN=0) and is accomplished by the following steps.
Disabling the BDM lockout is only possible in special modes
(SMODN=0). Follow the same steps as for enabling the BDM lockout,
but erase the SHADOW byte.
At the next reset, the SHADOW byte is loaded into the EEMCR register.
NOBDML bit in EEMCR will be set and BDM becomes operational.
When the BDM lockout is enabled it is not possible to run code from the
reset vector in special single chip mode.
1. Remove the SHADOW byte protection by clearing SHPROT bit in
2. Clear NOSHB bit in EEMCR register to make the SHADOW byte
3. Program bit 7 of the SHADOW byte like a regular EEPROM
4. Protect the SHADOW byte by setting SHPROT bit in EEPROT
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EEPROT register.
visible at $0FC0.
location at address $0FC0 (write $7F into address $0FC0). Do not
program other bits of the SHADOW byte (location $0FC0);
otherwise some regular EEPROM array locations will not be
visible. At the next reset, the SHADOW byte is loaded into the
EEMCR register. NOBDML bit in EEMCR will be cleared and BDM
will not be operational.
register.
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