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5.4 Micro controllers

A micro controllers can -when compared to a PC- best be seen as a small scale PC where almost all components reside on one chip. They are used inside (embedded in) all kinds of devices (e.g. Cell phones, instruments, cars, machines). Compared to a PC most micro controllers allow easy low level I/O, providing a flexible way to drive electro motors, other chips, etc. In general micro controllers are cheap, but also from other perspectives they can contribute to lower design costs: size, power consumption, weight, easy low level I/O, etc. In the setting of building a flight simulator cockpit the use of micro controllers can be seen as distributed computing, making it less complex to control a large amount of devices. The software for a micro controller is in general stored on an EPROM. Some micro controllers allow the use of separate additional chips for RAM and EPROM. Most micro controllers can be controlled from a PC by means of a parallel or serial type interface. In general the use of the micro controller itself is not over complicated, but is does require the acquisition of specific knowledge. In the remainder of this section some examples will be given.

5.4.1 OOPIC

A very advanced micro controller is the OOPic board (OOPic). Although having all the characteristics of a micro controller, it can more or less be handled as a PC, giving it a relative low entry level. In comparison to other micro controllers and apart from an interface cable no additional equipment (e.g. programming hardware, EPROM eraser) is needed to operate the board. The standard OOPIC programming language (object oriented) is Basic. The OOPIC basic is 100% compatible with Microsoft's Visual Basic (there is also support for C++ and Java). As a result of the object oriented approach, programming an OOPIC is straight forward and transparent. Especially interesting is the option to develop event driven routines triggered by the I/O interfaces of the board. Depending on the type of OOPIC board there are 16 or more Digital I/O lines and 4 Analog- to-digital converters. Additionally the OOPIC board comes with a range of integrated hardware circuits that relieve the user from having to build complicated interface circuitry. In most cases simply connecting the hardware directly to the OOPic is all that needs to be done. Available hardware circuits are: digital I/O lines, analog-to-digital converts, Pulse width modulators, timer/counters, EEPROM, serial port, keypad, servo controllers, etc. Starting with the OOPIC-R board a standard serial interface and a serial control protocol is included that allows a remote PC or any other device with a serial port to interact with, control and debug an OOPic application while it is running. Up to 127 OOPIC boards can be connected together via an build-in I2C network. Communicating over this network comes down to referring to a variable on an other (named) OOPic on the I2C network. The I2C network connection can also be used to drive additional devices that have a I2C interface such as for instance a LCD display.

The ease of use and the limited need for specialized knowledge makes the OOPIC board very attractive. On the OOPic site detailed background information is provided, including a large amount of sample code, links for discussion groups and suppliers.

5.4.2 Other micro controllers

In the table below various other brands of micro controllers are listed. All have a large number of possibilities and are (relatively) low cost.

5.4.3 Other sources of information

Within the area of (home) robotics there is a high interest in using micro controllers. A search on Internet will give many insights. For example the site GoRobotics is a nice starting point. At the end of 2006 Microsoft Robotics Studio was launched. This is a whole new platform for low level control of external devices and might become of interest for cockpit builders because of the resulting development of drivers for hardware. Additionally you will find a lot of information with this predefined search at Google, you can narrow it down by adding "cockpit", "simulation", "gauge", etc.