Kontron PCI-AOB16/12, Руководство пользователя

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PCI-AOB8/12 (16/12) User’s Guide
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Mode 2: Rate Generator
This mode provides a divide-by-N capability where N is the count loaded into the counter. When
triggered, the counter output goes low for one clock period after N counts, reloads the initial
count, and the cycle starts over. This mode is periodic, the same sequence is repeated
indefinitely until the gate input is brought low. This mode also works well as an alternative to
mode 0 for event counting.
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Mode 3: Square Wave Generator
This mode operates like mode 2. The output is high for half of the count and low for the other
half. If the count is even, the output is a symmetrical square wave. If the count is odd, the
output is high for (N+1)/2 counts and low for (N-1)/2 counts. Periodic triggering or frequency
synthesis are two possible applications for this mode. Note that in this mode, to achieve the
square wave, the counter decrements by two for the total loaded count, reloads, and then
decrements by two for the second part of the wave form.
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Mode 4: Software Triggered Strobe
This mode sets the output high and, when the count is loaded, the counter begins to count down.
When the counter reaches zero, the output will go low for one input period. The counter must be
reloaded to repeat the cycle. A low gate input will inhibit the counter.
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Mode 5: Hardware Triggered Strobe
In this mode, the counter will start counting after the rising edge of the trigger input and will go
low for one clock period when the terminal count is reached. The counter is retriggerable. The
output will not go low until the full count after the rising edge of the trigger.