Specifications

Processor Description (V40)
WCU - Wait Control Unit
The WCU provides added flexibility for interfacing to memory and
I/O that have varying speed requirements. The V40 includes three
internal bus masters that access memory and I/O devices. The number
of wait states inserted can be programmed separately for the CPU,
RCU, and DCU. The memory space can be divided into three
separate areas and the number of wait states defined differently for
each. The wait states are programmed through the WCY2, WCY1,
and WMB V40 configuration registers.
SCU - Serial Control
Unit
The serial control unit is a single asynchronous serial channel used for
serial communication between the V40 and a serial device external to
the V40. Programming the SCU is similar to programming the 8251A
Serial Control Unit for asynchronous modes of operation.
TCU - Counter/Timer Control
Unit
The Counter/Timer Control Unit includes three 16-bit programmable
counter/timers. These counter/timers can be used for SCU baud rate
generation, timing loops, timed and periodic interrupts, and external
asynchronous event counters. Programming the TCU is similar to
programming the 8254 Programmable Interval Timer, with a few
restrictions placed on operating modes because of the way the TCU is
connected internally to the V40.
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