Reverse Engineering MCU ATmega324PV to extract microcontroller ATmega324PV scheme, locate the fuse bit and crack MCU’s memory for Heximal reading;
These options should only be used when not operating close to the maximum frequency of the device, and only if frequency stability at start-up is not important for the application. These options are not suitable for crystals.
These options are intended for use with ceramic resonators and will ensure frequency stability at start-up. They can also be used with crystals when not operating close to the maximum frequency of the device, and if frequency stability at start-up is not important for the application if copy chip at89s8252 flash.
The device can utilize a 32.768 kHz watch crystal as clock source by a dedicated Low Frequency Crystal Oscillator. The crystal should be connected as shown in Figure 22. When this Oscillator is selected, start-up times are determined by the SUT Fuses and CKSEL0.
The calibrated internal RC Oscillator by default provides a 8.0 MHz clock. The frequency is nominal value at 3V and 25°C. The device is shipped with the CKDIV8 Fuse programmed. See “System Clock Prescaler” on page 48 for more details. This clock may be selected as the system clock by programming the CKSEL Fuses as shown in Table.
If selected, it will operate with no external components. During reset, hardware loads the calibration byte into the OSCCAL Register and thereby automatically calibrates the RC Oscillator. At 3V and 25°C, this calibration gives a frequency of 8 MHz ± 1%.
The oscillator can be calibrated to any frequency in the range 7.3 – 8.1 MHz within ±1% accuracy, by changing the OSCCAL register. When this Oscillator is used as the MCU clock, the Watchdog Oscillator will still be used for the Watchdog Timer and for the Reset Time-out. For more information on the pre-programmed calibration value when Recover chip pic16f913 binary.
The device is shipped with this option selected.
The frequency ranges are preliminary values. Actual values are TBD.
If 8 MHz frequency exceeds the specification of the device (depends on VCC), the CKDIV8 Fuse can be programmed in order to divide the internal frequency by 8. When this Oscillator is selected, start-up times are determined by the SUT Fuses.
The Oscillator Calibration Register is used to trim the Calibrated Internal RC Oscillator to remove process variations from the oscillator frequency. The factory-calibrated value is automatically written to this register during MCU reset, giving an oscillator frequency of 8.0 MHz at 25°C.
The application software can write this register to change the oscillator frequency. The oscillator can be calibrated to any frequency in the range 7.3 – 8.1 MHz within ±1% accuracy. Calibration outside that range is not guaranteed.