Register Details And Use
3.5.1 8 Mode V
Counter Register Setup
CM15 CM14 CM13 CM7 CM6 CM5
In this mode the gate input is used, as in mode S, to determine
which register will load the counter. The counter will be loaded
from the Load register when the gate input is low, and from
the Hold register when the gate input is high. The counter will
b e loaded when a LOAD command is issued, or when a TC
occurs. The counter will count repetitively once it is started.
A DISARM command is required to stop the counter.
3.5.1 9 Mode X
Hardware Save (available in AM 9513 A only)
CM1 5 CM1 4 CM13 CM7 CM6 CM5
E D G E
Mode X, provides a hardware sampling of the counter contents
without interrupting the count. A Load and Arm command or a
Load command followed by an Arm command is required to
initialize the counter. Once armed, a Gate edge starts the
counting operation; gate edges applied to a disarmed counter
are disregarded. After application of the Triggering Gate edge
the counter will count all qualified source edges until the first
TC, irrespective of the gate level. All gate edges applied during
the counting sequence will store the current count in the Hold
register, but they will not interrupt the counting sequence.
On each TC, the counter will be reloaded from the Load
register and stopped. Subsequent counting requires a new
triggering Gate edge; counting resumes on the first source
edge following the triggering Gate edge.
There is only one control register for the module. It is used to
assign parameters and manipulate each of the counters. The
CTRL register must be addressed by peripheral byte (PBxx)
and is only available as a write operation. If the user is going
to use the standard software (FB159), the CTRL register will
not be addressed directly. A description of each of the
functions is given in the preceding sections, along with the
equivalent "BEFn parameter assignments for FBI 59. FBI 59 is
described in Chapter 4.
Because of the processing time required by the
module when a control word is received, you must allow a
period of 500 microseconds for the module to process the
I f the module receives another control word in less than 500
microseconds, the first process will be interrupted. You can
test the Ready bit of the INTl register to be sure that the
module has processed its last control word and is available
Subaddres xxx0, Write
3.6.1 Control Words: CTRL7
These three bits are used to determine which function will
Title and Description
7 6 5
0 0 0
Parameter assignment; the parameters for
the selected counters will be transferred
from transfer memory area on the module
to the counters.
0 0 1
Start counter; the selected counters will
be started. This is a software start.
0 1 0
Load counter; the selected counters will
be loaded from either the Load or the Hold
register depending on which counting
mode is used.
0 1 1
Start counter; the selected
counters will be loaded and started in
the same operation. This can also be
considered an ARM command for a
counting mode with a hardware trigger.
1 0 0
Copy H to E; for the selected counters,
the contents of the Hold register will be
transferred to the counter.
1 0 1
Save counter; for the selected counters,
the contents of the counter will be
transferred to the Hold register. This
operation does not affect the operation of
1 1 0
Stop counter; theselected counters will be
stopped or disarmed. DISARM command.
1 1 1
Addition functions of the CTRL register are
called. These functions are described in
the next section. Bits 4 thru
of the CTRL
register perform differently than they do
in the abovementioned funtions.