D.12 Mode L waveform
Hardware-Triggered Delayed Pulse One-Shot
Mode L is similar to Mode J except that counting will not begin until a
Gate edge is applied to an armed counter. The counter must be armed
before application of the triggering Gate edge; Gate edges applied to a
disarmed counter are disregarded. The counter will start counting source
edges and counting will proceed until the second TC.
Note that after application of a triggering Gate edge, the Gate input will
be disregarded for the remainder of the count cycle. This differs from
Mode K, where the gate can be modulated throughout the count cycle to
stop and start the counter. On the first TC after application of the
triggering Gate edge, the counter will be reloaded from the
Hold
register.
On the second TC, the counter will be reloaded from the
Load
register
and counting will stop until a new edge is issued to the counter. Note
that unlike Mode K, new Gate edges are required alter every second TC
to continue counting.
SOURCE
COUNT
VALUE
TC OUTPUT
TC TOGGLED
OUTPUT
GATE
L-1
L-2
2
0
Mode L Waveforms
X
L
1
H
H-1
H-2
2
0
1
L
62