Mode 3 – Basic Operation (Odd Count); Mode 3 – Disabling The Count - Intel 386 User Manual

Intel386™ EX EMBEDDED PROCESSOR USER'S MANUAL
Control
Word = 16H
Writes to
Counter n
CLKIN n
GATE n
OUT n
?
Count
Figure 10-12. Mode 3 – Basic Operation (Odd Count)
For an even count of N, OUTn remains high for N/2 counts and low for N/2
counts (provided GATEn remains high). For an odd count of N, OUTn remains
high for (N + 1)/2 counts and low for (N – 1)/2 counts (provided GATEn
remains high).
Figure 10-13 shows suspending the counting sequence. A low level on GATEn causes the counter
to drive OUTn active (When OUTn is low, a falling edge on GATEn causes OUTn to be driven
high immediately) and suspend counting. A rising edge on the GATEn causes the counter to be
reloaded with the count. A high level on GATEn resumes counting.
Control
Word = 16H
Writes to
n
Counter
n
CLKIN
n
GATE
n
OUT
?
Count
10-14
Count = 5
? ? ? 0004 0002 0000 0004 0002 0004 0002 0000
NOTE
Count = 4
? ? ? 0004 0002 0004 0002 0002 0002 0004 0002
Figure 10-13. Mode 3 – Disabling the Count
0004 0002
A2400-01
0004 0002
A2401-02