Intel 386 User Manual

10-15
TIMER/COUNTER UNIT
Figure 10-14 and Figure 10-15 shows writing a new count. If the counter receives a gate-trigger
after writing a new count but before the end of the current half-cycle, the count is loaded on the
next CLKINn pulse and counting continues from the new count (Figure 10-14). Otherwise, the
new count is loaded at the end of the current half-cycle (Figure 10-15).
Figure 10-14. Mode 3 – Writing a New Count (With a Trigger)
Figure 10-15. Mode 3 – Writing a New Count (Without a Trigger)
????864286410
Writes to
Counter
n
CLKIN n
GATE n
OUT n
Control
Word = 16H
Count
86
Count = 8
Count = 10
A2407-02
A2406-01
????42424286
Writes to
Counter
n
CLKIN n
GATE n
OUT n
Control
Word = 16H
Count
42
Count = 4
Count = 8

Intel 386 Specifications

General

Architecture	x86
Clock Speed	12 MHz to 40 MHz
Transistor Count	275, 000
Data Bus Width	32-bit
Address Bus Width	32-bit
Instruction Set	x86
Introduced	1985
Maximum Memory	4 GB
Operating Modes	Real mode, Protected mode, Virtual 8086 mode
MMU	Yes
Voltage	5V
Model	Intel 386
Package	PGA
Process	1.5 μm to 1 μm