Integrating PJSIP with STM32H750B-DK + FreeRTOS + LwIP

[Artron]

Hello STM32 Community,

I am currently working on a VoIP project using the STM32H750B-DK and I am trying to integrate PJSIP/PJPROJECT into my STM32 application.

My current setup is:

• MCU/Board: STM32H750B-DK

• Core: ARM Cortex-M7

• RTOS: FreeRTOS

• Network stack: LwIP

• Ethernet PHY: LAN8742

• IDE: STM32CubeIDE

• Compiler: ARM GCC

• VoIP: PJSIP / PJPROJECT

• Audio: WM8994 codec

• RTP: Already implemented and tested separately

• G.711: PCMU implementation is also being integrated

Ethernet, LwIP, UDP and RTP communication are already working on my board. I can successfully exchange RTP packets and have been testing the network communication using Wireshark.

My current goal is to integrate SIP + RTP using PJSIP, so that the STM32 can eventually register with a SIP server and establish VoIP calls.

However, I am facing many compilation, configuration and integration errors while trying to port PJSIP to the STM32H750B-DK. I have tried configuring config_site.h, PJLIB, PJLIB-UTIL, PJSIP and the FreeRTOS-related settings, but I am still getting different build/configuration errors.

I have also tried adapting PJSIP configuration for:

• FreeRTOS

• ARM Cortex-M7

• LwIP

• No Linux/POSIX environment

• Static memory allocation

• Embedded environment

At this point, I would really appreciate guidance from anyone who has successfully integrated PJSIP/PJPROJECT on an STM32 MCU, especially STM32H7.

My questions

1. Is PJSIP/PJPROJECT practical on STM32H750 + FreeRTOS + LwIP without Linux?

2. Should I use the PJSIP socket abstraction or adapt it directly to the LwIP socket API?

3. Has anyone successfully implemented SIP registration + SIP call setup + RTP audio using PJSIP on an STM32H7?

I have already spent quite a lot of time trying different configurations, but I am running into a chain of compilation and porting issues.

If someone has a working STM32 + FreeRTOS + LwIP + PJSIP example/project, or can point me toward the correct integration approach, it would be extremely helpful.

Thank you in advance for any guidance.