| Computer Interfacing |
Parallel Port Output [header, example]
A PC's parallel port can be used to control things outside of the computer. Unfortunately, Linux makes direct port access a bit difficult. In order to control the parallel port, the user must be root or the program must be SUID, and the ioperm() function must be called. I have created a header called parport.h which allows for easy port output.
The only function in the header, ppout() converts a string of 1's and 0's into a decimal number, which is sent to the proper port (or ports, if the status port is used). The line
would set high the 8 data lines of the parallel port yet leave the status bits low. See the header file for more documentation.
LCD Interfacing
[header, example]
Any LCD module using the standard 14-pin interface can be hooked up to a computer and controlled. This header handles all of the low-level interfacing. Feed it a string and it appears on the LCD module.
This header requires parport.h.
Click on picture for schematic
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