LWIP - udp_new() returns PCB as NULL

[Mz.1]

Hi,

I decided to upgrade my STM32CubeMX to the latest version 6.9.1.

my project was generated first with STM32CubeMX 6.5.0 - so I had to copy the IOC manually.

I checked multiple times that all configuration is the same like it was, and it is.

when I'm calling the LWIP method udp_new() I'm getting NULL and than I can't send any UDP message.

I did a debug and notice this is happening under "do_memp_malloc_pool" function in the memp.c file

this is not happening in the old code generation.

it there special configuration that I'm not aware of?

thanks for the help!

[LCE · Accepted solution]

Don't know about Cube, but in some *opt.h file you can set the maximum number of UDP PCBs, have you checked that?

Do you get this error already on the first udp_new() ?

And depending on STM32 you have to take care where in the SRAM the lwip memory pool is placed.
That definitely applies to the H7.

[Mz.1]

@LCE thanks for your reply 🙂

> Don't know about Cube, but in some *opt.h file you can set the maximum number of UDP PCBs, have you checked that? yes it set to 4

> Do you get this error already on the first udp_new() ? yes on the first

[Pavel A.]

Debug. Go into udp_new().