Crack Locked ATMEGA128L AVR Chip
Crack Locked ATMEGA128L AVR Chip and readout atmega128l microcontroller flash memory firmware, the secured heximal file of atmega128l mcu can be deciphered from its flash memory;
When the WDE is written to logic one, the Watchdog Timer is enabled, and if the WDE is written to logic zero, the Watchdog Timer function is disabled to break off atmega128l chipset fuse bit. WDE can only be cleared if the WDCE bit has logic level one. To disable an enabled Watchdog Timer, the following procedure must be followed:
- In the same operation, write a logic one to WDCE and WDE. A logic one must be written to WDE even though it is set to one before the disable operation starts
- Within the next four clock cycles, write a logic 0 to This disables the Watchdog
- Bits .0 – WDP2, WDP1, WDP0: Watchdog Timer Prescaler 2, 1, and 0
The WDP2, WDP1, and WDP0 bits determine the Watchdog Timer prescaling when the Watch- dog Timer is enabled. The different prescaling values and their corresponding Timeout Periods are shown in Table 17.
The following code example shows one assembly and one C function for turning off the WDT. The example assumes that interrupts are controlled (for example, by disabling interrupts glob- ally) so that no interrupts will occur during execution of these functions.
In this mode, the Watchdog Timer is initially disabled, but can be enabled by writing the WDE bit to 1 without any restriction. A timed sequence is needed when changing the Watchdog Time-out period or disabling an enabled Watchdog Timer by breaking atmega128l microcontroller flash memory. To disable an enabled Watchdog Timer and/or changing the Watchdog Time-out, the following procedure must be followed:
- In the same operation, write a logic one to WDCE and WDE. A logic one must be written to WDE regardless of the previous value of the WDE bit
- Within the next four clock cycles, in the same operation, write the WDE and WDP bits as desired, but with the WDCE bit cleared