MAC_CTRL_TX_FLOW
mac |= MAC_CTRL_TX_EN | MAC_CTRL_TX_FLOW |
value |= (MAC_CTRL_TX_FLOW | MAC_CTRL_RX_FLOW);
value |= (MAC_CTRL_TX_FLOW | MAC_CTRL_RX_FLOW);
value |= (MAC_CTRL_TX_FLOW | MAC_CTRL_RX_FLOW);