Microcontrollers – Part 1: Introduction
Microcontrollers – there are tons of these small but smart electronic devices around us. They are in almost every modern kitchen device, in every car, in the entertainment children’s toys, in the modern cafe machine, in the smart battery chargers, etc.
Some people are familiar with the thematic, but for many other, the topic cоuld be helpful.
What is the Microcontroller Device? What does the microcontroller do?
From its name, you can make some guessworks. “Micro” – obviously the device generally has the little volume.
“Controller” – it is controlling some activity of something, It can control any processes and can be used in some kind of automatization of almost any process.
About their shape, count of their pins/leads the variants are hundreds. In the common case, the microcontroller unit has a rectangular shape.
Into the Microcontroller’s package has placed the MCU silicone chip, bonded with golden, thin as human hair wires to its leads.
PIC. 1 Silicone Crystal CHIP multicore MCU
Firstly, let we look on the controller as a closed black box. What we see – countless pins with unknown functions. Here is the magic – almost every Pin from this dramatic array is General-Purpose I/O (Input or Output).
The I/O pin (for clarity we named it PORT) can be configured as an input. On this input can be attached an analog or digital signals. That’s why the input can be configured as Analog, Digital, Pull-Up-ed or can be left free*. (need to be connected to signal source or Ground)
Analog input – The internal circuitry in most cases Multiplexed Inputs of the ADC engine (Analog-To-Digital Converter). The MCU is transforming the incoming analog value in thе exact moment, into the MCU readable 8-bit or 16- bit word.
Digital Input – The System reacts on the incoming signals as LOW i f they are below the (for example CMOS) Standard level or as High if the applied to port voltage is over the High-Level Limit. Between The levels are inserted protected zone, when the manner of MCU interpretation that value is unpredictable. Many MCU has inserted Bus keeper circuit to solve that problem – The system sticky pull-down or pull-up the signal to Ground (Vss) or Powering Voltage (Vcc).
Pull-Up-ed Digital Input – Many microcontrollers can be configured to switch on the weak Pull-upping Resistor (20 – 100K) between the PORT input and positive powering input (Vcc). That allows decreasing the count of external components, seen from hardware developing side.
The Port Can be configured as Digital Output – and can be set with one by two states – LOW or HIGH logical state or level.
Also, there are private cases of MCUs, allows configuring some their ports as Analog Output – Commonly DAC (Digital-To-Analog Converter) Output.
*(need to be connected to signal source or Ground)
As you probably know the base and more usable “Data” is One BYTE – It consists of 8-bits (The “bit” – is the small and undividable information part: YES or NO, High or Low ),
For comfortable usage by the hardware engineers, designers and programmers PORTs in the MCU often are assigned with Alphabetical Ordered.
FOR Example PORT-A 0..7 = 1 BYTE, PORT-B 0..7 ….., etc, where PORT-A.0 is equal of BIT-0 of PORT-A.
IF the PORTA.0 is High – There is controlling level for your first controlled LED – and if you change or toggle this port, the simple system is done – Your first flashing LED, controlled as you wish.
PIC. 2 It isn’t an insect – it is the idealized view of AVR RISC Microcontroller …
To Be Continued!
Dear Inventors, Don’t Stop To Think Positively!