Here's a comparison between the STM32F103C4 (ARM Cortex-M3) and the ATmega328P (AVR) microcontrollers, which highlights their core specifications, capabilities, and typical use cases.
The STM32F103C4 IC chip is shown below.
And the ATmega328P IC (used in Arduino Uno and Nano) is shown below.
| Feature | STM32F103C4 | ATmega328P |
|---|---|---|
| Core Architecture | ARM Cortex-M3 | AVR 8-bit |
| Clock Speed | Up to 72 MHz | 16 MHz |
| Flash Memory | 16 KB | 32 KB |
| SRAM | 4 KB | 2 KB |
| EEPROM | No internal EEPROM | 1 KB |
| Operating Voltage | 2.0V - 3.6V | 1.8V - 5.5V |
| GPIO Pins | 37 GPIO pins (shared with peripherals) | 23 GPIO pins |
| I/O Pin Voltage | 3.3V | 5V |
| Timers | 3 timers (1 advanced, 2 general-purpose) | 3 timers (1 8-bit, 2 16-bit) |
| Analog-to-Digital | 10 channels, 12-bit ADC | 6 channels, 10-bit ADC |
| PWM Channels | 12 channels | 6 channels |
| Communication Interfaces | 2x SPI, 2x I²C, 3x USART, 1x CAN, USB | 1x SPI, 1x I²C, 1x USART |
| DMA | 7 channels | None |
| Power Consumption | Low-power modes available (STOP, STANDBY) | Power-down and sleep modes |
| Debugging Interface | JTAG, SWD (Serial Wire Debug) | No dedicated debug interface (supports ISP) |
| Cost | Generally higher | Generally lower |
| Typical Applications | Industrial, consumer electronics, IoT | Hobby projects, basic embedded applications |
Key Differences and Considerations
Core and Performance:
- The STM32F103C4 uses a 32-bit ARM Cortex-M3 core, which is significantly faster and more powerful than the 8-bit AVR core in the ATmega328P.
- It also has a higher clock speed (72 MHz vs. 16 MHz) and supports more advanced arithmetic operations, enabling faster computation, especially for complex tasks.
Memory:
- The STM32F103C4 has 16 KB of Flash and 4 KB of SRAM, but it lacks EEPROM, which the ATmega328P has (1 KB).
- The ATmega328P has a larger Flash memory (32 KB), which can be more useful in simpler applications that require more program space but don’t need as much processing power.
Operating Voltage:
- The STM32F103C4 operates at 3.3V, whereas the ATmega328P can operate at 5V, which is often more compatible with many sensors and modules commonly used in hobbyist projects.
Peripherals and Communication:
- STM32F103C4 has more communication interfaces (multiple USARTs, SPI, I²C, CAN, and USB), making it more versatile for complex projects.
- The ATmega328P has only one interface for each type, which is typically sufficient for simpler projects.
Timers and PWM:
- STM32F103C4 has more and higher-resolution timers, making it better suited for applications that need precise timing and multiple PWM channels (such as motor control).
ADC Resolution:
- STM32F103C4 has a 12-bit ADC (higher resolution than the ATmega328P’s 10-bit ADC), providing more precise analog-to-digital conversions.
Debugging and Development:
- STM32F103C4 supports JTAG and SWD interfaces for debugging, which are valuable for development and troubleshooting.
- ATmega328P uses simpler In-System Programming (ISP) and doesn’t support advanced debugging interfaces without external debugging tools.
Typical Applications:
- STM32F103C4: Often used in more complex applications like industrial controllers, IoT devices, and systems needing efficient power management.
- ATmega328P: Ideal for simpler tasks, such as home automation, hobby projects, and educational purposes (e.g., Arduino Uno), due to its ease of use and broader support in maker communities.
Summary
The STM32F103C4 is a more powerful and versatile microcontroller compared to the ATmega328P, making it suitable for applications requiring higher processing power, more communication options, and precise analog measurements. The ATmega328P, however, is often more accessible and easier to integrate into simpler projects or prototypes due to its 5V compatibility and large community support.
Further Readings
What is ATmega328 used for? ATmega328 Applications
Programming ATmega328P ADC Interrupt
Programming ATmega328P Input Capture with Interrupt
