UART driver
Low-level serial communication provides the transport foundation for the protocol implementation.
02 / PROTOCOL ENGINEERING
Modbus
Slave
A complete slave device developed from first principles: UART driver, Modbus RTU stack, command processing, frame validation, and reliable communication over RS485.
Explore source code
RoleProtocol and driver development
StackEmbedded C / UART / RS485
FocusReliable multi-node communication
APPLICATIONCOMMAND PROCESSING
MODBUS RTUFRAME + CRC
UART DRIVERSERIAL I/O
RS485PHYSICAL BUS
0110 1011 0010 1101 0100
01 / THE BUILD
Protocol behavior,
implemented end to end.
Rather than relying on a prebuilt stack, this project implements the communication path from the UART driver upward. Incoming bytes are assembled into frames, validated, decoded, and routed to the correct command behavior before a compliant response is returned.
Building each layer directly made timing, framing, addressing, and error handling visible, turning the protocol specification into working device behavior.
Frame handling
Receives, assembles, validates, and interprets Modbus RTU request frames.
Command processing
Maps validated requests to device operations and constructs the correct slave response.
Multi-node validation
Tests communication behavior across multiple nodes on the shared RS485 physical layer.
02 / DATA PATH
Every byte has
a defined journey.
The implementation keeps physical transport, serial I/O, protocol rules, and application behavior separated. That layered structure makes the system easier to reason about, validate, and extend.
RS485 BUS
→
UART DRIVER
→
MODBUS STACK
→
DEVICE LOGIC
Responses return through the same layers in reverse after command execution and frame construction.