LPC1768 UART Firmware Replication - Chennai, India

I need expert freelancer in Chennai, India
1. Firmware Development
Develop firmware in C (CMSIS/Keil uVision 5) for NXP LPC1768 ARM Cortex-M3 MCU.
Configure and integrate 3 UART channels:
* Develop interrupt-driven UART communication (TX/RX), using ring buffer / circular buffer.
Replicate functionality of the existing working HEX file on the provided hardware and deliver complete, maintainable source code.

2. Protocol Integration
* Implement custom communication protocol compatible with existing application (framing, synchronization, packet validation).
* Support for command-response sequences and handling of variable-length message bytes.
* Ensure full functional equivalence with the reference HEX firmware.

3. Testing & Validation
* Develop test firmware for loopback and communication validation of RS232/RS485.
* Debug and validate communication using oscilloscope/logic analyzer.
* Integration testing with custom harness hardware and host PC application.