2026-06-04 3:18 AM - last edited on 2026-06-04 3:48 AM by mƎALLEm
I have a custom board with STM32H723VGT6 and external ethernet PHY LAN8742, I have configured MPU, ETH, lwip using cubeMX, for now i just want to ping my device, i am not using RTOS. In debugging, I can see that i am getting ARP requests in network and also those which are meant for myself with proper source and destination IP, but while allocating pbuf for Tx packets it is failing (no free space in heap)(required only 60 bytes).
i have also followed other methods like sown in - https://github.com/stm32-hotspot/STM32H7-LwIP-Examples/tree/main
by enabling seperate MPU region for tx/rx descriptor, but that also made same problem.
below is my MPU configurations ->speculative default mode is enabled,
using Static IP
linker script
ethenet settings,
now in code i am unable to allocate memory in function
etharp_input(struct pbuf *p, struct netif *netif) -->
where can i be wrong
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