Firmware Development for Transformer‑Based Li‑ion Home UPS (Renesas RL78 or STM32G081)

Project Title:
Firmware Development for Transformer‑Based Li‑ion UPS (Renesas RL78 or STM32G081)

Description:
We are developing a transformer‑based inbuilt Li‑ion Home UPS. The hardware (transformer + PCBA) is complete, and the schematic currently uses a Renesas RL78 controller. We require professional support for firmware/program development.

We are open to two approaches:

Continue with Renesas RL78 as per schematic.

Migrate to STM32G081 for modular, future‑proof firmware with LCD integration.

Key Requirements:

Battery management (CC/CV charging, cutoff at 3.65V/2.8V per cell)

Inverter control (SPWM generation, overload and short‑circuit protection)

Protections (over‑voltage, under‑voltage, over‑current, thermal)

LCD/LED section integration for status display

Modular, audit‑ready code structure with documentation

Deliverables:

Working firmware code (Renesas IDE or STM32CubeIDE)

Documentation for compliance/audit readiness

Support for testing and validation on hardware

Budget:
₹30,000 – ₹50,000 (depending on scope and documentation level)

Timeline:
4–6 weeks

Milestone Plan:

Option A – Renesas RL78

M1: Basic firmware setup (mains sense, relay, protections)

M2: Charging logic + current amplifier section

M3: LCD/LED integration + documentation

Option B – STM32G081 Migration

M1: STM32 initialization + battery cutoff logic

M2: SPWM inverter control + protections

M3: LCD integration + modular documentation

Notes:

Please specify whether you propose Renesas RL78 or STM32G081.

Provide a milestone cost split and timeline for your approach.
Only bids mentioning controller choice + milestone plan will be shortlisted.