Register Details And Use
3.3.5 Scaler 2 (FOUT) Enable: MM12
This bit of the MM register is used to enable and disable the
output of scaler 2 (FOUT). The default value of 0 will enable
the FOUT signal.
3.3.6 Scaler 1 Counting Mode: MM1 5
This bit is used to set the counting mode of Scaler 1. The
default value of 0 will place the output of Scaler 1 in the
binary counting mode.
Scaler 1 in binary counting mode
Scaler 1 in BCD counting mode
Scaler 1 Outputs
Input Frequency: 2MHz
: l 0
: l 6
3.3.7 Bits MM14 and MM 13
Bits MM 14 and MM1 3 of the MM register are not available to
the user on the 6ES5 242 module. These bits are used by
the 8085 firmware. The condition of these bits is irrelevant.
3.4 CM -Counter Mode Register (AM 9513)
There are,five CM registers on the AM 9513, one for each
counter. The CM register is used to assign the operation
parameters for the counters.
The CM register is a 16-bit register that is divided into nine
sections. These nine sections are used to select the operating
mode of the counter. The bit assignments of the CM register
and their meanings are listed below.
CM-Low Order Byte
Subaddres xxx9, Write
Subaddress xxx8, Write
Pulse Edge Selection
3.4.1 Output Selection: CM2
CM0 of the CM registers allow selection of several
different counter output modes. The output of each counter
is connected to the' AM 9519 interrupt controller and also to
the respective front connector of the module.
Active high, TC Pulse mode
TC Toggled mode, start low
TC Toggled mode, start high
Active low, TC Pulse mode
Terminal Count: The point in time where the counter value
reaches a value of zero. This is the point where the counter
output will change state. The following is a listing of the
conditions that will cause TC to occur on the next count.
When using the counter outputs of the AM 9513 you must
remember that all outputs switch on TC, which means that
all counting operations depending on a switched output must
either count down to TC, or count up to TC, to achieve the
TC Pulse mode: This mode will produce an output when the
count value equals zero. The output will become active on the
leading edge of TC. The width of the output pulse depends on
the time the counter isat azerovalue. Active high and active low
simply mean the state of the pulse during the time the counter
is at zero value.
TC Toggle mode: This mode will produce an output level
instead of a pulse. This level will toggle between the high and
the low states on the trailing edge of TC.
Special Function enable