|Multifunctional Keypad (MFK)|
|The equipment in an aircraft are automatically controlled
by a central computer, known as the Mission Computer (MC).
The MC interacts with the other avionics equipment through three MIL-STD-1553 communication buses. Multi Function Keyboard (MFK) is one such equipment. It is used to communicate with the pilot about the status of various equipment and the navigation.
The MFK has, at its heart, a MOTOROLA 68000 series processor with ROM, RAM and EEPROM memory to carry out its task. The MFK is the pilot interface for all communications with MC or other equipment through MC. It is connected to one of the 1553 buses, used by MC for data communication. It is also connected to the Multi Function Rotary switch (MFR) through a RS422 interface.
The MFK has a built-in display unit and a keyboard. The display unit is LCD based. The keyboard has provisions to enter alphabetic and numeric values. There are a number of control buttons to facilitate the pilot communication with MC.
The software has been developed as a real time, embedded application. The development platform includes the C Language, pSOS real-time kernel, and the 68000 series Assembly Language. Teamwork Case Tool was used during system analysis. It was also used for the preparation Software Requirement Specification.
The MFK software provides various functionalities to assist effective communication with MC. These messages are handled by MFK in the following three different modes of operations.
The software is capable of receiving the page information
from MC in binary format and validate them. Upon valid information, it converts them into
pilot readable alphabetic and numeric values before displaying the page on the screen. The
software can also process page requests from the pilot and send that message to MC to get
the details for a new page.
During identification, MFK sends the hardware and software
version number to MC. The software sends all its MC messages to Coding and Control Unit
(CCU) also. This enables the CCU to take charge of the system, in case the MC fails for
some reasons. The software comes with a built-in test feature to ensure its proper