MTD_TXBUF_SIZE
size = MTD_NUM_RXD * MTD_RXBUF_SIZE + MTD_NUM_TXD * MTD_TXBUF_SIZE;
+ (i - MTD_NUM_RXD) * MTD_TXBUF_SIZE);
+ index * MTD_TXBUF_SIZE;
} else if (tlen > MTD_TXBUF_SIZE) {