Core issue
The %GT96K_FEWAN-5-UNDERFLOW:Transmit underflow on int [chars] error message is received because a Tx underflow condition has occurred. Part of the packet data was not available while transmission was in progress. While a frame was transmitted, the local buffer of the GT96K controller chip received insufficient data because data was not transferred to the chip fast enough in order to keep the transmission speed with its output rate. Normally, such a problem is temporary, which depends on transient peak loads within the system. The Memory access delays can result from this situation.
Resolution
If this issue occurs, allow the system to correct itself. The system should recover automatically. No action is required. Refer to GT96K_FEWAN Messages for more information on GT96K_FEWAN error messages.