Posted on April 04, 2017 at 16:141)How can detect why I lost my connection?
Not sure why you think you lose the connection.
From your netInitialize() call, I cannot see if you acquire a TCP or UDP socket.
But TCP connections do not close immediately, if not explicitly done. And UDP is connection-less.
I guess the issue is the same as for question 2.
2)why do I miss some packets when I send them via PC ?
You might need to qualify your network environment, and test under controlled conditions.
'Normal' office networks involve a lot of 'irrelevant' traffic, directed to other PC nodes, switches, etc.
The STM32F4 simply does not have the performance resources to process all packets in an average office network environment.
I suggest the 'Wireshark' software to monitor and evaluate the network traffic you are dealing with.
And for test purposes, I suggest to connect the STM board to the 'PC' side to a separate network via a separate network adapter, unaffected by above mentioned 'office traffic'. A RNDIS device (USB to ethernet) is affordable and easy to install.
This way, you can easily add additional stress in a controlled way to test you application.
1)coud you explain how can define minimum time between sending packet according to their length?
Not sure if I understand that correctly, but this would depend on your application.
2)did I define well the Heap and Stack size for my MCU and Ethernet threads?
There are no fixed rules I know of. If your application runs properly, the sizes are o.k. This means you require proper testing, including stress tests / overload test. You application shall react in a defined manner (drop packages, return error codes ?), but not crash the system (Hardfault).
You can initialize the stack with a specific pattern, and inspect the stack memory after a test run. This will tell you a 'high water mark'.
RTOSs use to complicate things, every task use to have his own stack. Often, the RTOS documentation gives recommendations about stack sizes - at least FreeRTOS does ...
