AT89C55WD-24JU

The operating range of the AT89C55WD microcontroller mentioned in the document is 4.0V to 5.5V .

The AT89C55WD microcontroller has a total of six interrupt sources according to the document. These include two external interrupts (INT0 and INT1), three timer interrupts (Timers 0, 1, and 2), and the serial port interrupt. Each of these interrupt sources can be individually enabled or disabled by setting or clearing a bit in the Special Function Register IE.

The AT89C55WD microcontroller supports two power-saving modes: Idle Mode and Power-down Mode. In Idle Mode, the CPU puts itself to sleep while all on-chip peripherals remain active, and the mode is invoked by software. The content of the on-chip RAM and special function registers remain unchanged during this mode. Idle Mode can be terminated by any enabled interrupt or by a hardware reset. On the other hand, Power-down Mode saves the RAM contents but freezes the oscillator, disabling all other chip functions until the next external interrupt or hardware reset. .