I am trying to create a simple client/server demo sending small packets across the network using a loopback interface on my EFM32 GG Cortex-M3 microcontroller. I have copied verbatim the example code given on the freeros website here https://www.freertos.org/FreeRTOS-Plus/FreeRTOSPlusTCP/TCPNetworkingTutorialReceivingTCPData.html and here https://www.freertos.org/FreeRTOS-Plus/FreeRTOSPlusTCP/TCPNetworkingTutorialSendingTCPData.html for sending and recieving. In my main function I simply call the FreeRTOSIPStart() function (which replaces the FreeRTOSIPInit function) and then starts the threads, main function looks like this: ~~~ void main ( void ) { CHIPInit(); SWOSetupForPrint(); extern NetworkInterfacet *xLoopbackInterface; pxLoopbackFillInterfaceDescriptor(1, xLoopbackInterface);

FreeRTOS_AddNetworkInterface(xLoopbackInterface);
FreeRTOS_IPStart();

xTaskCreate(prvEchoClientRxTask, "rx", 300, NULL, 1U, &RXTask);
xTaskCreate(vTCPSend, "tx", 300, NULL, 2U, &TXTask);
vTaskStartScheduler();
for(;;){
    puts("shouldnt be here");
}
return;

} ~~~ I am unsure whether or not the way I have initialised the interface is right or not – I am using the FreeRTOS +TCP unofficial release with the loopback NetworkInterface.c Stepping through, I meet my first problem in FreeRTOS_connect, when the prvConnectStart( pxSocket, pxAddress) is called the socket has not yet been bound, so goes into the condition that binds the socket… ~~~ else if( socketSOCKETISBOUND( pxSocket ) == pdFALSE ) { /* Bind the socket to the port that the client task will send from. Non-standard, so the error returned is that returned by bind(). */ xResult = FreeRTOS_bind( ( Socket_t ) pxSocket, NULL, 0u ); } ~~~ xResult becomes zero here, indicating a successful bind. Back in the connect function, xResult becomes equal to the return value of FreeRTOS_issocketconnected( pxSocket ); which is 0. The code then finally gets stuck looping in the idle hook after xEventGroupWaitBits() is called. I am using GCC compiler and am programming on Silicon labs’ IDE ‘Simplicity Studios’. Thanks for any help!