User`s guide

Device Driver Blocks

9-15

executed at the specified rate. Specifically, when the digital output block is

executed, it causes corresponding boolean values to be output from the

board’s digital I/O channels.

Adding Device Driver Blocks to the Model

Add device driver blocks to the Simulink block diagram as you would any other

block — simply drag the block from the block library and insert it into the

model. Connect the ADC or Digital Input module to the model’s inputs and

connect the DAC or Digital Output module to the model’s outputs.

Including Device Driver Code

Device driver blocks are implemented as S-functions written in C. The C code

for a device driver block is compiled as a MEX-file so that it can be called by

Simulink. See the MATLAB Application Program Interface Guide for

information on MEX-files.

ThesameCcodecanalsobecompiledandlinkedtothegeneratedcodejustlike

any other C-coded, S-function. However, by using the target (

.tlc)filethat

corresponds to each of the C file S-functions, the device driver code is inlined in

the generated code.

The

matlabroot\rtw\c\dos\devices directory contains the MEX-files, C files,

and target files (

.tlc) for the device driver blocks included in doslib.This

directory is automatically added to your MATLAB path when you include any

of the blocks from

doslib in your model.