Measurement Computing CIO-DIO48 Digital Output

CIO-DIO48 Digital Output block (not recommended)


Simulink® Real-Time™ Library of Drivers No Longer Recommended for Use


The CIO-DIO48 has two 8255 chips (1,2). Each chip has three ports (A,B,C). Each port has a maximum of 8 digital I/O lines that can be configured as inputs or outputs.

Use a separate driver block for each port. By selecting the digital output driver block, the port is configured as output.

Scaling Input to Output

I/O Module Output

Block Input Data Type




< 0.5 = TTL low
≥ 0.5 = TTL high

Block Parameters

Channel vector

Enter numbers between 1 and 8 to select the digital output lines used with this port. This driver allows the selection of individual digital output lines in arbitrary order. The number of elements defines the number of digital lines used.

For example, to use all of the digital outputs for one port, enter


Number the lines beginning with 1 even if this board manufacturer starts numbering the lines with 0.


From the list choose either A, B, or C. The I/O board has two 8255 chips with 3 ports. The Port parameter defines which port of the 8255 chip is used for this driver block. Each port has a maximum or 8 digital lines that can be configured as inputs or outputs depending on which driver block is chosen. In each case, one block is required for each port.

Reset vector

The reset vector controls the behavior of the channel at model termination. Enter a scalar or a vector that is the same length as the channel vector. If you specify a scalar value, that setting is replicated over the channel vector. If you specify a value of 1, the corresponding channel is reset to the value specified in the initial value vector. If you specify a value of 0, the channel remains at the last value attained while the model was running.

Initial value vector

The initial value vector contains the initial values (0 or 1) of the output channels. Enter a scalar or a vector that is the same length as the channel vector. If you enter a scalar, that value is replicated as the initial value over the channel vector. The channels are set to these initial values between the time the model is downloaded and the time it is started.


From the list choose 1 or 2. The Chip parameter defines which of the two 8255 chips is used.

Sample time

Enter the base sample time or a multiple of the base sample time (-1 means sample time is inherited).

Base address

Enter the base address of the board. This entry must correspond to the DIP switch setting on the board. For example, if the DIP switch setting is 300 (hexadecimal), enter 0x300.

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