HT46RU22 Datasheet, Holtek Semiconductor

* Operating voltage:
* Up to 0.5ms instruction cycle with 8MHz system clock fSYS=4MHz: 2.2V~5.5V fSYS=8MHz: 3.3V~5.5V
* 19 bidirectional I/O lines (max.)

that interface directly to analog signals, such as those from sensors. The advantages of low power consumption, I/O flex.