Asynchronous Serial Communications Programmer's Reference Manual (32022-90052)

2 Controlling Asynchronous Devices

Programmatically

Programmatically Once an asynchronous device is properly connected

and conﬁgured on a HP 3000 Series 900 computer, it can be accessed

programmatically through the MPE/iX File System. The File System

interfaces with the ASC software, which communicates with the device

based on its port conﬁguration. Your program has only to treat the

device as a ﬁle a deviceﬁle, and the computer will handle the actual

communication with the device, including use of the proper protocol.

This chapter discusses how the File System, system intrinsics, and your

program can work together to control an asynchronous device. The

following topics are discussed:

• An overview of File System functions.

• Device operation modes.

• Use of intrinsics.