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.