Versatile Interface Adapter (VIA)

The following information applies to both the Chip and Core versions of this 65xx brand microprocessor family member.

WDC's high volume production proven 65xx brand microprocessor family of manually designed GDSII hard cores are highly optimized cores that are small and low power and therefore an excellent choice for low power System-on-Chip (SoC) ASIC microcontroller designs. These static cores support a wide range of applications from radiation resistant hi-rel applications such as medical implantable life-support devices to ultra high volume consumer devices.

The W65C22S Versatile Interface Adapter (VIA) is a flexible I/O device for use with the 65xx series microprocessor family. The W65C22S includes functions for programmed control of two peripheral ports (Ports A and B). Two program controlled 8-bit bi-directional peripheral I/O ports allow direct interfacing between the microprocessor and selected peripheral units. Each port has input data latching capability. Two programmable Data Direction Registers (A and B) allow selection of data direction (input or output) on an individual line basis. Also provided are two programmable 16-bit Interval Timer/Counters with latches. Timer 1 may be operated in a One-Shot Interrupt Mode with interrupts on each count-to-zero, or in a Free-Run Mode with a continuous series of evenly spaced interrupts. Timer 2 functions as both an interval and pulse counter. Serial Data transfers are provided by a serial to parallel/parallel to serial shift register. Application versatility is further increased by various control registers, including an Interrupt Flag Register, an Interrupt Enable Register and two Function Control Registers. The IRQB output is an open drain.