cc1200 AP sJoinSem

Hi All

my platform is TM4C129+CC1200 , now I encouter a problem:

        if (sJoinSem && (sNumCurrentPeers < NUM_CONNECTIONS))
        {
            //
            // Listen for a new incoming connection.
            //
            while (1)
            {
                if (SMPL_SUCCESS == SMPL_LinkListen(&sLID[sNumCurrentPeers]))
                {
                    break;
                }
            }

            sNumCurrentPeers++;
            sJoinSem--;
        }

static uint8_t
sCB(linkID_t lid)
{
    //
    // Have we been sent a frame on an active link?
    //
    if (lid)
    {
        sPeerFrameSem++;
    }
    else
    {
        sJoinSem++;
    }

    //
    // Leave the frame to be read by the main loop of the application.
    //
    return 0;
}

when I reset ED, the ED work normally, but AP cannot reach the sJoinSem++ , but can reach the MRFI_GpioIsr(); this means the AP receive the packet from ED , but cannot trig the callback function, I don't kow why