Week 4

Embedding Programming

We have reached week 4 of the Fab Academy (who would have thought I would be here 😅). Well, it's the week of embedded programming 🤯🙈. It's amazing what the world of microcontrollers, chips and connections is.

Learning about how small electronic/digital devices work is an interesting adventure, and here I share what I have learned so far. Let's go!

Micro-controllers

They are small programmable devices that are present in various devices. They consist of three functional units: central processing unit, memory, and input/output peripherals. Through the input and output pins, it is capable of executing commands stored in its memory.

Commonly with the following features:

• Central processing unit -ranging from small and simple 4-bit processors to complex 32-bit or 64-bit processors.
• Volatile memory (RAM) for data storage
• ROM, EPROM, EEPROM or Flash memory for program and operating parameter storage.
• Discrete input and output bits, allowing control or detection of the logic state of an individual package pin.
• Serial input/output such as serial ports (UARTs)
• other serial communications interfaces like I²C, Serial Peripheral Interface and Controller Area Network for system interconnect.
• Peripherals such as timers, event counters, PWM generators, and watchdog.
• Clock generator - often an oscillator for a quartz timing crystal, resonator or RC circuit.
• Many include analog-to-digital converters, some include digital-to-analog converters.
• In-circuit programming and in-circuit debugging support.

Programming languajes

In my limited programming experience 😰, I must say that this week was the opportunity to explore more about other programming languages that I had already heard of. That is the case of the C++ language.

For my inquiries about it, I rely on the W3S page that has a very simple language to teach a variety of programming languages.

Micropython, On my part, it is more familiar to me since I had some introduction to Python before, whether in bootcamps or online courses. And thanks to the review of the documentation, I understand that it is based on the C language. 🤯

Practice with Arduino UNO

As a first experience with Arduino, I used the Wokwi simulator. Here, I am sharing my experience. Firstly, I wrote the code using programming materials, in this case, C++.

Code

                                // the setup function runs once when you press reset or power the board
                                void setup() {
                                // inicializar el pin pin LED_BUILTIN digital como un output.
                                pinMode(LED_BUILTIN, OUTPUT);
                                }

                                // the loop function runs over and over again forever
                                void loop() {
                                digitalWrite(LED_BUILTIN, HIGH);  // turn the LED on (HIGH is the voltage level)
                                delay(1500);                      // wait for a second
                                digitalWrite(LED_BUILTIN, LOW);   // turn the LED off by making the voltage LOW
                                delay(1500);                      // wait for a second
                                }
                            

Then I run the Code, and the light is connected!!! I like this

Blink LED_BUILTIN Simulation - Arduino UNO - on Wokwi.

Then, I added an external LED and a resistor to the simulator.

Based on the blink code for the internal LED, I replaced some data: Before the line void setup(), the corresponding pin for the LED (pin 13) is declared. Then, in the pinMode() and digitalWrite -high and low- lines, we can indicate the number 13 that we assigned to the LED. I made the connections: Pin 13 to the anode and the GND pin to the cathode. 🤩 Awesome!!

Code

                                    int LED = 13;
                                    void setup() {
                                    // put your setup code here, to run once:
                                    pinMode(13, OUTPUT);
                                    }
                                    
                                    void loop() {
                                    // put your main code here, to run repeatedly:
                                    digitalWrite(13, HIGH);  // turn the LED on (HIGH is the voltage level)
                                    delay(1500);                      // wait for a second
                                    digitalWrite(13, LOW);   // turn the LED off by making the voltage LOW
                                    delay(1000);                      // wait for a second
                                    }
                                

Blink LED OUTPUT Simulation - Arduino UNO - on Wokwi.

A second practice in the Wokwi simulator with Arduino was a classic instruction programming: print ‘Hello world’. For then, I was a start a new project Arduino UNO from Scratch. I write a code for the ‘Hello world’, and ‘voilá’… in the virtual terminal was print the phrasse 😎.

With our fellows, we named the controllers with compound names, as a way to have fun and get fond of the microcontrollers 😊. Now, Arduino UNO is 'Arduardo' 🥸 and my Raspberry Pi Pico is ‘Raul Ricardo Pico’ 😎.

Code

                                    void setup() {
                                        // put your setup code here, to run once:
                                        Serial.begin(9600);
                                        Serial.println("Hello Arduardo!");
                                      }
                                      
                                      void loop() {
                                        // put your main code here, to run repeatedly:                                
                                      }                                      
                                

For the external communication test, I used the Arduino IDE and a USB type B connection.ardware with a USB conection. In the Arduino IDE, I pasted the same code written in Wokwi, uploaded it, and then observed that the light is on 🤩.

Blink code

Hello 'Arduardo' code

Video 'blink' reply.

Another piece of information that I found interesting about Raspberry, is that the post-fix numeral on RP2040 comes from the following:

1. Number of processor cores (2)
2. Loosely which type of processor (M0+)
3. floor(log2(ram / 16k))
4. floor(log2(nonvolatile / 16k)) or 0 if no onboard nonvolatile storage

Practice with Raspberry Pi Pico

For the RP Pi Pico practice, I used the Wokwi simulator and Thonny IDE again for peripheral communication. Here is my experience:

On Wokwi, I started a new project, this time using the MicroPython on Pi Pico option. Then, I started writing the 'Blink' code first, and then 'Hello World'. Both were successful 😎

Code Blink

                                        from machine import Pin, Timer
                                        led = Pin(25, Pin.OUT)
                                        timer = Timer()

                                        def blink(timer):
                                            led.toggle()

                                        timer.init(freq=2.5, mode=Timer.PERIODIC, callback=blink)
                                    

Then I run the Code, and the light is connected!!! I like this

Here, I used the same code, in Thonny IDE

An here, the reply in RP hardware, connected with a micro USB:

Code Hello World

                                            print("Hello, Raul Pico!")
                                        

                                            import utime

                                            while True:
                                                print('Hello, Raul Ricardo Pico');
                                                utime.sleep(1.5);
                                        

Then I run the Code, and the light is connected!!! I like this

And a 'Hello world' reply in a virtual terminal of Thonny IDE: