Entry points

The driver need have only 5 entry points:

read

returns the data requested. Returns -1 if an error occurs.

write

A dummy entry point. Returns -1 if invoked.

open

Prepare the port for use. Set up baud rate, parity, etc. Allocate any system resources required.

close

Disassociate the port with the MCB task. This call should release any resources claimed in the open call.

ioctl

Do device specific control. This will be used to perform the read and write functions, as well. The device parameters will be passd in through the arg function of the ioctl() routine.

There are 2 other entry points defined for the drivers in vxWorks, that will probably not be needed. These are the creat() and remove() functions.