Embedded Programming
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Objective of this Week
- Browse through the datasheet for our microcontroller
- Compare the performance and development workflows for other architectures
Datasheet
A Datasheet is a detailed document provided by the manufacturer that contains essential information about the microcontroller's specifications, features, and usage guidelines. Some of it includes as,
- Electrical Characteristics – Operating voltage, power consumption, and current ratings.
- Pin Configuration – Details on each pin’s function, including power, input/output, and special-purpose pins.
- Memory Details – Information on Flash memory, RAM, and EEPROM for code and data storage.
- Peripherals and Interfaces – Built-in modules like ADCs, timers, PWM, UART, SPI, and I2C for communication and control.
- Clock and Timing Information – Internal and external clock sources, oscillators, and timers.
- Programming and Debugging – Supported programming methods, bootloader options, and debugging interfaces.
- Performance and Operating Conditions – Processing speed, power modes, and environmental limits.
How it helps?
Component Selection – Helps engineers choose the right microcontroller for their application.
Circuit Design – Ensures correct connections and power requirements.
Firmware Development – Provides register addresses, memory maps, and peripheral control details for writing code.
Troubleshooting – Helps diagnose issues related to power, communication, or functionality.
Microcontrollers
A Microcontroller (MC, UC, or μC) or microcontroller unit (MCU) is a compact computer integrated into a single chip. It includes one or more processor cores (CPUs), memory, and programmable input/output (I/O) peripherals. The chip also contains program memory, such as NOR flash, OTP ROM, or ferroelectric RAM, along with a small amount of RAM. Unlike microprocessors, which are used in personal computers with multiple external components, microcontrollers are specifically designed for embedded applications.
Features:
- Processor (CPU) – Executes instructions and controls operations.
- Memory – Stores program code (Flash) and temporary data (RAM).
- Input/Output Ports (I/O) – Interfaces with external components like sensors, motors, and LEDs.
- Communication Interfaces – Supports protocols like UART, SPI, and I2C for data exchange.
- Timers and PWM – Used for task scheduling and controlling devices like motors.
- Analog-to-Digital Converter (ADC) – Converts analog signals to digital values.
- Low Power Modes – Optimized for battery-powered applications
Types:
- 8-bit MCUs (example - ATmega328) – Simple applications like automation and IoT.
- 16-bit MCUs (example - MSP430) – Medium-complexity applications like motor control
- 32-bit MCUs (example - STM32, ESP32) – High-performance applications like robotics and AI-based systems.
In this weekly assignment we are planning to do understanding of ESP32 Microcontroller.
ESP32
The ESP32 is a powerful Wi-Fi and Bluetooth-enabled microcontroller developed by Espressif Systems. It features a dual-core 32-bit Xtensa LX6 processor, running up to 240 MHz, with 520 KB SRAM and 4 MB flash memory (varies by model). It supports Wi-Fi (802.11 b/g/n), Bluetooth 4.2/BLE, GPIOs, ADC, DAC, SPI, I2C, UART, and PWM. Known for its low power consumption and high performance, it is widely used in IoT, robotics, automation, and embedded systems.
| Feature | Description |
| Digital Pins | Works as on/off switches to control LEDs, sensors, and motors. |
| Analog Pins | Reads varying voltage levels, useful for sensors like temperature and light sensors. |
| PWM Pins | Simulates analog output by quickly switching on/off, used for dimming LEDs or controlling motor speed. |
| I2C Interface | Allows multiple devices to communicate using two wires (SDA, SCL), commonly used for sensors and displays. |
| UART Interface | Enables serial communication with computers, microcontrollers, or other peripherals. |
| SPI Interface | High-speed communication protocol for connecting peripherals like SD cards and displays. |
| Wi-Fi & Bluetooth | Built-in connectivity for IoT applications, supporting both Wi-Fi and Bluetooth (BLE). |
| Touch Pins | Special pins that detect touch input, useful for touch-sensitive applications. |
| DAC (Digital-to-Analog Converter) | Converts digital signals to true analog output, unlike PWM. |
| Deep Sleep Mode | Power-saving mode to reduce energy consumption, ideal for battery-powered projects. |
Specification:
| Item | Value |
| CPU | Dual-core Tensilica Xtensa LX6 processor (up to 240 MHz) |
| Flash Memory | Varies (External SPI Flash, typically 4MB–16MB) |
| SRAM | 520KB |
| Digital I/O Pins | 34 |
| Analog I/O Pins | 18 (ADC) |
| PWM Pins | Available on most digital pins |
| I2C Interface | 2 |
| SPI Interface | 4 |
| UART Interface | 3 |
| Wi-Fi | 802.11 b/g/n (2.4 GHz) |
| Bluetooth | Bluetooth 4.2 + BLE |
| Power Supply & Downloading Interface | Type-C / Micro USB (depends on the board) |
| Power | 3.3V DC |
| Dimensions | Varies by board (ESP32-WROOM: 18×25.5×3.1mm) |
| Programming Language | Arduino, MicroPython, ESP-IDF |
Pinout reference for ESP32:
Pin Description:
| Name | Description |
| GPIOx | General-purpose digital input/output (I/O) pins. Some support internal pull-up/down resistors, PWM, and peripheral functions. |
| ADCx | Analog-to-Digital Converter (ADC) pins, used for measuring analog signals. ESP32 has multiple ADC channels with 12-bit resolution. |
| DACx | Digital-to-Analog Converter (DAC) pins, capable of producing analog voltages. Two DAC channels are available. |
| HSPIx / VSPIx | Hardware SPI interfaces for high-speed serial communication. ESP32 supports multiple SPI buses. |
| I2C SDA / SCL | I2C interface for communication with sensors and peripherals. Any GPIO can be configured as I2C. |
| UARTx TX/RX | Universal Asynchronous Receiver-Transmitter (UART) for serial communication. ESP32 supports multiple UART ports. |
| PWMx | Pulse Width Modulation (PWM) capable GPIOs, used for motor control, LED dimming, etc. |
| EN (Enable) | Chip enable pin. High to activate the chip, low to disable it and enter low power mode. |
| BOOT / IO0 | Used for entering the bootloader mode during programming. Pulled low during flashing. |
| GND | Ground connection. Required for circuit reference. |
| VCC (3.3V) | Main power supply input (3.3V). ESP32 operates at 3.3V logic levels. |
| 5V (USB VBUS) | Provides 5V from the USB input, often used to power external components. |
| VP / VN | Capacitive touch sensor input pins that also function as ADC inputs. |
| RTS / CTS | Request to Send (RTS) and Clear to Send (CTS) flow control signals for UART communication. |
| EXT_RSTB | External reset pin. Pulling low resets the ESP32. |
ESP32 Datasheet - Link
Comparison of Microcontrollers
We compare the ESP32 with ESP8266,
| Parameters | ESP32 | ESP8266 |
| Microcontroller | ESP32 | ESP8266 |
| Core | Dual core | Single core |
| Architecture | 32-bit LX6 (600 DMIPS) | 32-bit LX106 |
| Clock Speed | Up to 240MHz | Up to 160MHz |
| Operating Voltage | 3.3V | 3.3V |
| GPIO Voltage | 3.3V | 3.3V |
| Digital Pins | 36 | 16 |
| PWM Pins | 32 | 16 |
| Analog Pins | 15 | 1 |
| SPI/I2C/UART/I2S | 4/2/2/2 | 2/1/2/2 |
| Wi-Fi | Yes | Yes |
| Bluetooth | Yes | No |
| Built-in Sensors | Touch, Temperature, Hall Effect | No |
| Programming Languages | Arduino IDE, C/C++, MicroPython | Arduino IDE, C/C++, MicroPython, JavaScript |
| On-board Programming LED | D2 pin | D0 pin |
| Flash | 4MB | 4MB |
| RAM | 520KB | 128KB |
| EEPROM | No | 520B |
| Advantages | Best for IoT projects, supports Wi-Fi & Bluetooth, more GPIOs, better performance | Best for basic IoT projects, lower power consumption |
Conclusion
- ESP32 is ideal for advanced IoT projects requiring high processing power, dual-core performance, Wi-Fi, Bluetooth, and multiple peripherals. It suits applications like smart home automation, industrial IoT, and real-time data processing.
- ESP8266 is a cost-effective choice for basic IoT applications with Wi-Fi connectivity. It is suitable for simple web servers, remote monitoring, and home automation projects where Bluetooth and high-performance processing are not needed.