5. Embedded Programming - AJWZ¶

ATtiny (Jenna)¶

ATTINY412 Information¶

I consulted the datasheet for information. I looked at the 412 data as opposed to the 212, which has less general capablility. I found the list of features and listed the ones that caught my attention, as well as their significance.

8 bit CPU
- The Central Processing Unit (CPU) processes data in 8 bits
- Allows 256 different values
- Simple processing capability
128B EEPROM
- Electrically Erasable Programmable Read-Only Memory (EEPROM) of 128 bytes
- Amount of data retained while on or off
- Can be reprogrammed through voltage
256B SRAM
- Static Random Access Memory (SRAM) of 256 bytes
- Amount of data retained while on and working
- Wiped when turned off
- Works faster and costs more than Dynamic Access Memory (DRAM)
Single Pin Unified Program Debug Interface (UPDI)
- Programmer for ATmega microcontrollers
- Reset pin used
- Dedicated pin to support more data
Six Channel Event System
- Six different routes for peripheral signals to reach others
- Creates connections between devices
Temperature range -40°C-105°C (-40°F-221°F)
- Operates within this temperature
- Risk of overheating or decrease in longevity outside range

I also referenced the pinouts and listed the pinouts with more detail on what the functions accomplish.
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Pin	Function	Definition
1	VDD	Voltage input
2	PA6	Digital I/O and analog pin 6
3	PA7	Digital I/O and analog pin 7
4	PA1	Digital I/O and analog pin 1
5	PA2	Digital I/O pin 0, reset, and UPDI location
6	PA0/GND/UDPI	Digital I/O and analog pin 6
7	PA3/EXTCLK	Digital I/O and analog pin 3 and external clock
8	GND	Ground

I consulted the block diagram after. Instead of interpreting each specific block, I observed the connections to the main bus. I noticed that clocks and detectors connect less directly to the bus. In contrast, the memory systems, CPU, and UPDI programmer are more readily accessible.
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Programming¶

I could program the ATtiny412 and use an adapter to run the code from Arduino IDE. However, our lab uses Arduinos as programmers for the ATtiny412 since we have extra, so I documented that process.

Download
- Download Arduino AVR on the Arduino version 1.18.19. This supports ATtiny-412.
- Download megaTinycore zip file
Extract zip file
- Find Arduino sketchbook folder through preferences
- Create hardware folder in sketchbook folder, add megatinycore.master
- Download and extract jtag.updi zip
Sketch
Move jtag.updi to sketch folder
Paste example code into jtag
!
Upload
- Save and compile in jtag mode
- Plug into hardware with pinouts wired properly

ATtiny Source Code¶

// the setup function runs once when you press reset or power the board
void setup() {
  // initialize digital pin LED_BUILTIN as an 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(1000);                       // wait for a second
  digitalWrite(LED_BUILTIN, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);                       // wait for a second
}

ESP32-C3 (Zaina)¶

First I used WokWi to simulate C++ blinking LED using a button for a C3.

My original code for this did not work so I asked Tyler Russell for help and he provided me this code to stimulate the C3.

int buttonState = 0;

void setup()
{
 pinMode(D6, INPUT);
 pinMode(D2, OUTPUT);
}


void loop()
{
 // read the state of the pushbutton value
 buttonState = digitalRead(D6);
 // check if pushbutton is pressed.  if it is, the
 // buttonState is HIGH
 if (buttonState == HIGH) {
   // turn LED on
   digitalWrite(D2, HIGH);
 } else {
   // turn LED off
   digitalWrite(D2, LOW);
 }
 delay(10); // Delay a little bit to improve simulation performance
}

I then took the C++ code and used Arduino IDE to light up. The only problem with this was my button placement. I placed my button across the USB-C port, so it was over the button when I put the cord in the C3.

C3 Arduino video

After I got my WokWi simulation working and lit up my LED using Arduino IDE, I followed this tutorial to download and set up Thonny onto my device.

First I downloaded Thonny and when I was in Thonny I went into tools and selected options. In the option I go under the interpreter tab and select MicroPython ESP32.

After I choose my device I plug my C3 while holding the boot button on it. After my device is plugged in I go back into the interpreter and select Install or update MicroPython(esptool) I then select these options to install esptool.

After I successfully installed Thonny, I asked ChatGPT to change my original C++ code to micro python language.

from machine import Pin
import time

# Setup pin modes
button = Pin(0, Pin.IN, Pin.PULL_UP)  # GPIO 6 (D6 pin) as input with internal pull-up resistor
led = Pin(28, Pin.OUT)                 # GPIO 2 (D2 pin) as output

while True:
    # Read the state of the button
    button_state = button.value()

    # If the button is pressed, the button_state will be 0 (since we use a pull-up resistor)
    if button_state == 1:
        led.value(1)  # Turn LED on
    else:
        led.value(0)  # Turn LED off

    time.sleep(0.01)  # Delay a little bit to improve simulation performance

I used this code given to me by Chatgpt and put it into Thonny.

RP2040 (Andrew)¶

Since Wokwi doesn’t have a XIAO RP2040, I used the XIAO Esp32-C3 for my design because it has the same pinouts as the RP2040.

This is the code I used:

const int buttonPin = D0;     // the number of the pushbutton pin
const int ledPin =  D1;      // the number of the LED pin

int buttonState = 0;         // variable for reading the pushbutton status

void setup() {
  // initialize the LED pin as an output:
  pinMode(ledPin, OUTPUT);
  // initialize the pushbutton pin as an input:
  pinMode(buttonPin, INPUT);
}

void loop() {
  // read the state of the pushbutton value:
  buttonState = digitalRead(buttonPin);

  // check if the pushbutton is pressed. If it is, the buttonState is HIGH:
  if (buttonState == HIGH) {
    // turn LED off:
    digitalWrite(ledPin, HIGH);
  } else {
    // turn LED on:
    digitalWrite(ledPin, LOW);
  }
}

I copy and pasted this code into the Arduino IDE and used the Board Manager to set my chip to the Xiao Rp 2040. Then I selected the right com port and hit verify and send.

To get the RP2040 I had to copy a library onto my IDE.

The Code:

MicroPython MicroPython was a really interesting experience. All of the frustration I had was with downloading the libraries, but when it came to actually coding I found it really easy.

I followed this tutorial to get it to work.

The change was really simple, all that had to be done was to change the interpreter to recognize the Rp2040.

The only major issue I faced this unit was when I tried to use the Thonny interpreter to flash my RP2040 I was not letting me install it. To fix this I pressed boot on the RP2040, and reopened thonny, which resolved my issues.

Picture of code:

If everything is working correctly it looks like this.

Arduino Uno (Wilson)¶

The Arduino Uno is very user friendly and is a great starting micro-controller for beginners. Not only is it affordable, it also comes with a wide variety of sensors that and modules. Some cons that it has, however, is its limited processing power, power limitations, and limit on pin quantity.

To make the Arduino Uno run a blink program, I first needed to know the pinout. Here it is. !()[https://www.electronicshub.org/wp-content/smush-webp/2021/01/High-Res-Arduino-UNO-Pinout.jpg.webp]

After learning the pinouts, I was able to quickly generate a simple button code from the going to Arduino IDE’s examples and then I change the buttonPin and ledPin variables to 9 and 12 respectively.

Following this TinkerCAD simulation that I had used as a base for the other micro-controllers, I assembled the wiring on a breadboard. Then, after compiling the code in Arduino IDE and setting the COM port and setting the board to Arduino Uno, I uploaded the code into the Arduino.

Code:

/*
  Button

  Turns on and off a light emitting diode(LED) connected to digital pin 13,
  when pressing a pushbutton attached to pin 2.

  The circuit:
  - LED attached from pin 13 to ground through 220 ohm resistor
  - pushbutton attached to pin 2 from +5V
  - 10K resistor attached to pin 2 from ground

  - Note: on most Arduinos there is already an LED on the board
    attached to pin 13.

  created 2005
  by DojoDave <http://www.0j0.org>
  modified 30 Aug 2011
  by Tom Igoe

  This example code is in the public domain.

  https://www.arduino.cc/en/Tutorial/BuiltInExamples/Button
*/

// constants won't change. They're used here to set pin numbers:
const int buttonPin = 2;  // the number of the pushbutton pin
const int ledPin = 13;    // the number of the LED pin

// variables will change:
int buttonState = 0;  // variable for reading the pushbutton status

void setup() {
  // initialize the LED pin as an output:
  pinMode(ledPin, OUTPUT);
  // initialize the pushbutton pin as an input:
  pinMode(buttonPin, INPUT);
}

void loop() {
  // read the state of the pushbutton value:
  buttonState = digitalRead(buttonPin);

  // check if the pushbutton is pressed. If it is, the buttonState is HIGH:
  if (buttonState == HIGH) {
    // turn LED on:
    digitalWrite(ledPin, HIGH);
  } else {
    // turn LED off:
    digitalWrite(ledPin, LOW);
  }
}

Here is the working product of the Arduino making an LED turn on when the button is pressed.

Last update: March 25, 2025