Specifications

Software Crestron SIMPL Windows
Buffer
Lights_Scene_1
VProj_Power_Off
Screen_Up
Lights_Scene_2
VProj_Power_On
Screen_Down
1 enable
in1
in2
in3
in4
in5
in6
out1
out2
out3
out4
out5
out6
Buffer
To
Devices
press115
press116
press117
press118
press119
press120
press121
press122
press123
press124
press125
fb115
fb116
fb117
fb118
fb119
fb120
fb121
fb122
fb123
fb124
fb125
Touchpanel
System_On
System_Off
You will notice two interesting features about this example. First, the enable input
has a signal called ‘1’ connected to it. Earlier in the manual we described this special
signal as a digital signal that always has a value of logic high. In this case, this will
cause the Buffer to be permanently enabled. This is useful when you are using the
Buffer not to control the flow of signals, but to ‘map’ one signal name into many
others, as we have done here. The second unique feature of this example is the fact
that we have used the same signal name multiple times in the input side of the Buffer.
This allows multiple output signals to be driven high when a single input signal goes
high. Finally, notice that because the input/output pairs of the Buffer are independent
of one another, we have used a single symbol to generate the system on and system
off sequences. However, for clarity we could have just as correctly used two separate
symbols.
State Logic
The previous section discussed some of the most commonly used basic logic
elements. This section will cover commonly used symbols that contain state
information. That is, the symbols described here provide the most basic form of
memory in a SIMPL program. Realize however that this memory is volatile, and any
stored information will be lost if the program is reset or the control system is
powered off.
The fundamental difference between the symbols in this section and those in the
previous section, are that the states of the output signals cannot be determined by
evaluating the current state of the input signals. Instead, it is something that
happened in the past that has caused the outputs to attain their current states. This is
where the concept of memory comes from. In addition, the input signals for these
symbols are considered “edge-triggered,” meaning that the output signal states
depend on input signal transitions. In most cases, symbols are positive edge-
triggered, in that an input changing from low to high will cause an output change. In
some cases, however, inputs can be negative edge-triggered, and thus a transition
from high to low will affect the outputs. Symbols discussed in the last section are
46 • Crestron SIMPL Windows Primer – DOC. 6253