The P80C31SBAA can operate up to 12 MHz with an external clock source, but it's recommended to use a maximum frequency of 11.0592 MHz for reliable operation.
The oscillator circuit requires a crystal oscillator with a frequency of 11.0592 MHz, and the XTAL1 and XTAL2 pins should be connected to the crystal oscillator. The capacitor values for the oscillator circuit can be calculated using the formula provided in the datasheet.
The I/O pins can source or sink up to 15 mA of current, but it's recommended to limit the current to 10 mA or less to ensure reliable operation.
The WDT can be enabled by setting the WDTE bit in the WDT control register. The WDT timeout period can be set using the WDT prescaler and the clock frequency. The WDT can be reset by writing a specific sequence to the WDT control register.
The EA pin is used to enable or disable the external program memory. When EA is high, the microcontroller uses the internal program memory. When EA is low, the microcontroller uses the external program memory. The EA pin should be connected to VCC or GND depending on the desired configuration.
