Stuck in netconn_write if calling task uses to low prio!

Discussion created by lpcware Employee on Jun 15, 2016
Content originally posted in LPCWare by tjoAG on Tue Jan 15 03:53:01 MST 2013
Hi all

I have a LPC1788 running FreeRTOS and lwIP.

When a task, using netconn_write function, has a to low FreeRTOS priority, then it can lockup sometimes.

I have a function I use for sending Ethernet data via the netconn API.
To protect the TX function I use a critical section so one task can complete the transmit before a new one can do it.

But if I the calling task has a low FreeRTOS priority the task is stuck in the netconn_write(..) function??
It seems strange to me. It never returns from it.

Using higher priority, seems to solve the issue.

If the calling tasks has priority of at least 3, it seems to be fine. (I haven't tried higher)
The lwip recevie, transmit and tcp_ip task has the FreeRTOS priority at 3,3 and 4

The NVIC priority are set accordingly to Cortex M3 and FreeRTOS guideline. (Higer is lower:-))

Any idea why it does that?