STM32H725 Firmware Development

Embedded Firmware Developer Needed – STM32H725 (FreeRTOS, LwIP, LittleFS) – Stabilisation + Feature Completion

Project Summary

I am building an embedded product based on an STM32H725 microcontroller. The firmware stack is partially implemented but currently unstable. I need an experienced embedded developer to fix the low-level issues, stabilise the platform, and assist with completing the system features.

I will provide my full existing development codebase, including older revisions where all peripheral drivers and subsystems were working, so you can reference or reuse known-good implementations.


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Current Firmware Architecture

MCU: STM32H725VGH6 (Cortex-M7)

RTOS: FreeRTOS

Network Stack: LwIP (TCP/IP), custom HTTP server logic

File System: LittleFS on external NOR flash (MX25LM51245G)

Storage Role: Serves HTML/JS/CSS assets and configuration files

Boot/Init: Custom UART logger, hardware bring-up for I2C, SPI, RTC, EEPROM, IO expander, magnetometer

Build Environment: STM32CubeIDE + CubeMX base configuration



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Problems That Need to Be Resolved

The system is functional in parts but suffers from low-level stability issues:

1. Ethernet / LwIP Bring-Up Instability

Network stack sometimes fails to start

PHY link polling can freeze the MCU

Accept() / recv() behaviour inconsistent during HTTP operations

Occasional crashes during early network initialisation


2. LittleFS + NOR Flash Issues

System can freeze during block erase or file operations

Web asset upload API unstable (HTTP 411 errors, hangs, partial writes)

Need reliable directory creation, file write/append, and safe mount/format flows


3. General System Stability

Boot sequence sometimes halts at peripheral init

Task starvation or deadlocks under specific network activity

Race conditions between HTTP thread, flash operations, and network callbacks



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Deliverables

I need a developer who can:

Review and refactor the current firmware architecture

Identify root causes of freezes and race conditions

Integrate known-good drivers from my older codebase

Stabilise FreeRTOS task interactions (HTTP, flash, network, logger)

Ensure LwIP is initialised cleanly and robustly

Make LittleFS fully reliable under load

Provide debugging insight and recommended improvements

Produce clean, maintainable code following best practices



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What I Will Provide

Full access to my current project source

Older working revisions with stable drivers (for PHY, NOR, logging, etc.)

Hardware available for testing via remote support if required

UART logs, boot traces, and test cases



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Desired Skills

Strong experience with STM32H7 series

Deep understanding of FreeRTOS (scheduling, priorities, stack use)

Expert in LwIP internals (netconns, raw API, memory pools, threading rules)

Experience with NOR flash and LittleFS

Ability to debug complex freezes and race conditions

Efficient, methodical problem-solving ability



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Project Goal

A reliable, production-ready embedded firmware base that:

Boots cleanly

Brings up Ethernet/LwIP consistently

Serves web assets from LittleFS without freezing

Supports safe file upload and storage

Runs stable under continuous operation