Advanced Procedures (Real-Time Windows Target)

Real-Time Windows Target

Counter Input Block

This Real -Time Windows Target I/O blocks allow you to select and connect specific counter input channels to your Simulink model.

After you have added a Counter Input block to your Simulink model, you can enter the parameters for this I/O driver. This procedure uses Humusoft's MF604 I/O board as an example:

Double-click the Counter Input block.

The Block Parameters: Counter Input dialog box opens.

In the Sample time box, enter the same value you entered in the Fixed step size box from the Simulation Parameters dialog box. For example, enter

```
0.001
```

In the Input channels box, enter a channel vector that selects the counter input channels you are using on this board. The vector can be any valid MATLAB vector form. For example, to select all 4 counter input channels on the MF604 board, enter

```
[1,2,3,4] or [1:4]
```

From Reset after read, which determines if the counter should be reset to zero after its value has been read, choose one of the following options:

never -- Do not reset after reading.
always -- Always reset after reading.
level -- Reset after reading is block input is nonzero. This will add an input to the Counter Input block.
rising edge -- Reset after reading if block input changes from zero to nonzero between the last two successive readings. This will add an input to the Counter Input block.
falling edge -- Reset after reading if the block input changes from nonzero to zero between last two successive readings. This will add an input to the Counter Input block.
either edge -- Reset after reading if the block input changes either from zero to nonzero or from nonzero to zero between the last two successive readings. This will add an input to the Counter Input block.

From Clock input active edge, which determines which clock edge should increment the counter, select:

rising -- Low to high transitions
falling -- High to low transitions

Not all counter chips support selecting the input edge. In this case, the pull-down menu will reflect the supported option only.

From Gate input functionality, which defines the action of the counter's gate pin, select:

none -- Gate is disabled.
enable when high -- Counting is disabled when the gate is low and enabled when the gate is high.
enable when low -- Counting is disabled when the gate is high and enabled when the gate is low.
start on rising edge -- Counting is disabled until low to high transition of the gate occurs.
start on falling edge -- Counting is disabled until high to low transition of the gate occurs.
reset on rising edge -- Counter is reset when low to high transition of the gate occurs.
reset on falling edge -- Counter is reset when high to low transition of the gate occurs.
latch on rising edge -- The count of the counter is remembered when low to high transition of the gate occurs.
latch on falling edge -- The count of the counter is remembered when high to low transition of the gate occurs.
latch & reset on rising edge -- The count of the counter is remembered and then the counter is reset when low to high transition of the gate occurs.
latch & reset on falling edge -- The count of the counter is remembered and then the counter is reset when high to low transition of the gate occurs.

Not all counter chips support all gate modes. Only supported gate modes are shown in the pull-down menu.

Do one of the following:

Click Apply to apply the changes to your model and leave the dialog box open.
Click OK to apply the changes to your model and close the Block Parameters: Counter Input dialog box.

Digital Output Block Encoder Input Block