Other microcontroller features

Microcontrollers usually contain from several to dozens of general purpose input/output pins (GPIO). GPIO pins are software configurable to either an input or an output state. When GPIO pins are configured to an input state, they are often used to read sensors or external signals. Configured to the output state, GPIO pins can drive external devices such as LEDs or motors.

Many embedded systems need to read sensors that produce analog signals. This is the purpose of the analog-to-digital converter (ADC). Since processors are built to interpret and process digital data, i.e. 1s and 0s, they are not able to do anything with the analog signals that may be sent to it by a device. So the analog to digital converter is used to convert the incoming data into a form that the processor can recognize. A less common feature on some microcontrollers is a digital-to-analog converter (DAC) that allows the processor to output analog signals or voltage levels.

In addition to the converters, many embedded microprocessors include a variety of timers as well. One of the most common types of timers is the Programmable Interval Timer (PIT). A PIT may either count down from some value to zero, or up to the capacity of the count register, overflowing to zero. Once it reaches zero, it sends an interrupt to the processor indicating that it has finished counting. This is useful for devices such as thermostats, which periodically test the temperature around them to see if they need to turn the air conditioner on, the heater on, etc.

A dedicated Pulse Width Modulation (PWM) block makes it possible for the CPU to control power converters, resistive loads, motors, etc., without using lots of CPU resources in tight timer loops.

Universal Asynchronous Receiver/Transmitter (UART) block makes it possible to receive and transmit data over a serial line with very little load on the CPU. Dedicated on-chip hardware also often includes capabilities to communicate with other devices (chips) in digital formats such as I²C and Serial Peripheral Interface (SPI).

Higher integration

Micro-controllers may not implement an external address or data bus as they integrate RAM and non-volatile memory on the same chip as the CPU. Using fewer pins, the chip can be placed in a much smaller, cheaper package.

Integrating the memory and other peripherals on a single chip and testing them as a unit increases the cost of that chip, but often results in decreased net cost of the embedded system as a whole. Even if the cost of a CPU that has integrated peripherals is slightly more than the cost of a CPU and external peripherals, having fewer chips typically allows a smaller and cheaper circuit board, and reduces the labor required to assemble and test the circuit board.

Do the following tasks:

- Find all the abbreviations in the text, write them down.

- Give their meanings.

What Is a Control Engineer?

by David M. Koenig

So far we have implied that a control engineer designs control algorithms. In fact, the title of control engineer can mean many things. The following list, in no particular order, covers many of these "things":

1) Installer of control! instrumentation equipment (sometimes called an "instrumentation engineer"): In my experience this is the most prevalent description of a control engineer's activities. In this case, the actual design of the control algorithm is usually quite straightforward. The engineer usually purchases an off-the-shelf controller, installs it in an instrumentation panel, probably of her design, and then proceeds to make the controller work and get the process under control. This often is not trivial. There may be control input sensor problems. For example, the input signal may come from a thermocouple in an electrically heated bath of some kind and there may be serious common and normal mode voltages riding on the millivolt signal representing the thermocouple value. There may be control output actuator problems. There may be challenging process dynamics problems, which require careful controller tuning. In many ways, instrumentation engineering can be the most challenging aspect of control engineering.

2) Control algorithm designer: When off-the-shelf controllers will not do the job, the scene is often set for the control algorithm designer. The vehicle may be a microprocessor with a higher-level language like BASIC or a lower-level language like assembly language. It may even require firmware. Many control/instrumentation engineers fantasize about opportunities like this. They have to be careful to avoid exotic custom undocumented algorithms and keep it simple.

3) Process improvement team member: Although this person is trained in control engineering, success may result from solving process problems rather than installing new control algorithms.

4) Process problem solver: This is just a different name for the previous category although it may be used when the team members have developed a track record of successes.

Do the following task:

- Write down the translation of the text into Russian.