The R6522 Versatile Interface Adapter (VIA) is a very flexible I/O control device. In addition, this device contains a pair of very powerful 16-tiit interval timers, a senal-to-parallel/parallel-to serial shift register and input data latching on the peripheral ports.
Expanded handshaking capability allows control of bidirectional data transfers between VIA's in multiple processor systems.
The R6522 includes functions for programmed control of up to two peripheral devices (Ports A and B) These two program controlled 8-bit bidirectional 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.
The R6522 also has two programmable 16-bit Interval Timer/Counters with latches. Timer 1 may be operated in a OneShot 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-toparallel/parallei-to-senal shift register. Application versatility is further increased by various control registers, including—the Interrupt Flag Register, the Interrupt Enable Register, the Auxiliary Control Register and the Peripheral Control Register.
Features
• Two 8-bit bidirectional I/O ports
• Two 16-bit programmable timer/counters .
• Serial bidirectional peripheral I/O
• TTL compatible peripheral control lines
• Expanded "handshake” capability allows positive control of
data transfers between processor and penpheral devices
• Latched output and input registers on both I/O ports
• 1 and 2 MHz operation
• Commercial and industrial temperature range versions
• Single + 5 Vdc power requirement
