Hello guys, welcome back to our blog. Here in this article, I will discuss why baud rate is important in embedded systems, and why each system has different baud rates.

Ask questions if you have any electrical, electronics, or computer science doubts. You can also catch me on Instagram – CS Electrical & Electronics

Also, read:

Why Baud Rate Is Important In Embedded Systems

In embedded systems, communication between different components (microcontrollers, sensors, actuators, and communication interfaces) plays a crucial role. Two fundamental concepts in serial communication are baud rate and bit rate. These parameters determine the speed and efficiency of data transmission over a communication channel.

What is Baud Rate?

Baud rate is the number of signal changes (symbols) per second in a communication channel.

It is measured in bauds (Bd).
If a system transmits 1000 symbols per second, the baud rate is 1000 Bd.
Each symbol may carry one or more bits.

If a communication system transmits 10,000 bits per second (bps), and each symbol carries 2 bits, the baud rate would be:

Baud rate defines the number of signal changes per second, not necessarily the number of bits transmitted per second.

What is Bit Rate?

Bit rate refers to the number of bits transmitted per second (bps – bits per second).

A system that transmits 1000 bits per second has a bit rate of 1000 bps.
Bit rate depends on the baud rate and the number of bits encoded in each symbol.

If a system has a baud rate of 5000 Bd, and each symbol represents 4 bits, then the bit rate would be:

Bit rate measures the actual data transfer speed in terms of bits per second.

Baud Rate Vs Bit Rate

Parameter	Baud Rate	Bit Rate
Definition	Number of symbols per second	Number of bits per second
Measured in	Baud (Bd)	Bits per second (bps)
Affected by	Modulation technique	Baud rate & encoding scheme
Relationship	May be equal to or less than bit rate	Always equal to or greater than baud rate
Example	9600 Bd in UART (each symbol = 1 bit)	9600 bps for standard UART

Why Do Different Systems Have Different Baud Rates and Bit Rates?

01. Communication Protocols & Standards

Different communication protocols (UART, CAN, SPI, I2C, LIN, Ethernet) have predefined baud rate ranges based on the required reliability, noise immunity, and efficiency.

Protocol	Common Baud Rates (Bd)
UART	9600, 115200
CAN Bus	125K, 250K, 500K, 1M
SPI	1M, 4M, 8M
I2C	100K, 400K, 1M
Ethernet	10M, 100M, 1G

02. System Requirements

Real-time systems (automotive, industrial automation) need high baud rates to reduce latency.
Low-power systems (IoT sensors) use lower baud rates to conserve energy.

03. Noise and Signal Integrity

Higher baud rates are prone to noise and interference.
Lower baud rates provide better reliability over longer distances.
In automotive applications (e.g., CAN Bus), the baud rate is chosen based on cable length and electromagnetic interference (EMI).

04. Hardware Capabilities

Microcontrollers and peripherals have limitations on maximum baud rate support.
Example: Some MCUs support UART at 1 Mbps, while others may only support 115200 bps.

05. Error Handling and Synchronization

Higher baud rates may lead to synchronization errors.
Lower baud rates ensure stable communication, especially in noisy environments.

Purpose of Baud Rate and Bit Rate in Embedded Systems

01. Efficient Data Transmission

Ensures faster communication between MCUs, sensors, and peripherals.
Example: UART at 115200 bps transmits data faster than 9600 bps.

02. Compatibility with Communication Protocols

Ensures that devices speak the same language using standardized baud rates.
Example: A CAN Bus system in a vehicle uses a 500K baud rate to ensure compatibility across ECUs.

03. Balancing Speed and Reliability

High baud rate → Faster communication but prone to errors.
Low baud rate → Slower but more reliable.

04. Reducing Power Consumption

Lower baud rates require less processing power and energy.
Example: IoT devices use low baud rates to extend battery life.

05. Avoiding Data Loss and Corruption

Higher bit rates require robust error handling (parity bits, CRC, checksums).
Example: CAN Bus uses error detection mechanisms to ensure data integrity at high baud rates.

Examples of Baud Rates in Embedded Systems

01. UART Communication (Serial)

Standard baud rates: 9600, 19200, 38400, 57600, 115200, 1M bps
Used in microcontroller-to-PC communication (debugging), GPS modules, and Bluetooth modules.

02. CAN Bus (Automotive)

Standard baud rates: 125K, 250K, 500K, 1M bps
Used in engine control units (ECUs), ABS, powertrain, and ADAS.

03. SPI Communication

Standard speeds: 1M, 4M, 8M, 16M bps
Used in: Flash memory, SD cards, high-speed sensors.

04. I2C Communication

Standard speeds: 100K, 400K, 1M bps
Used in: Temperature sensors, EEPROM, display modules.

04. Ethernet

Standard speeds: 10M, 100M, 1G bps
Used in: Internet-connected embedded devices, industrial automation.

Choosing the Right Baud Rate for Your System

Application	Recommended Baud Rate
Debugging via UART	115200 bps
Low-power IoT devices	9600 – 57600 bps
Automotive CAN Bus	500K – 1M bps
SPI Sensors	4M – 16M bps
Ethernet	100M – 1G bps

Factors to Consider:

✅ Speed vs. reliability: Higher baud rates may introduce noise.

✅ Hardware limitations: Check the microcontroller’s supported baud rates.

✅ Cable length and noise: Longer cables require lower baud rates for signal integrity.

Conclusion

Baud rate refers to the number of signal changes per second.
Bit rate refers to the number of bits transmitted per second.
Different systems use different baud rates based on hardware, communication protocol, noise tolerance, and power consumption.
Choosing the right baud rate ensures efficient, reliable, and low-power data transmission in embedded systems.

By understanding baud rate and bit rate, you can optimize embedded communication protocols for your specific application, whether in automotive, IoT, or industrial automation. 🚀

This was about “Why Baud Rate Is Important In Embedded Systems“. Thank you for reading.

Also, read:

About The Author

Chetan Shidling

Automotive | Technical Blogger | Engineer | Content Creator

See author's posts

Share Now