Specifications

Processor Description (V40)
ICU - Interrupt Control Unit
Interrupts provide an efficient interface between the V40 CPU and
supporting peripheral devices. The ICU supports eight interrupts
directly and can be cascaded with other interrupt controllers, such as
the 8259A Programmable Interrupt Controller, to support additional
interrupting sources. Programming the ICU is similar to programming
the 8259A.
DCU - DMA Control
Unit
The DCU controls high speed data transfer between I/O and memory
devices. The DCU is similar to the 8257 Programmable DMA
Controller except that the DCU supports the full 1 Mbyte of V40
addressing space.
5-22