+}
+
+/** Finaliza el envío del frame
+ * @precond netdev_send_start() debe haber sido ejecutada
+ * @precond se copiaron datos al dispositivo para enviar
+ * @param len Cantidad de bytes a transmitir
+ */
+void netdev_send_end(byte len)
+{
+ // Set transmit page start to indicate packet start.
+ write_reg(TPSR, TX_PAGE_START);
+
+ // Ethernet packets must be > 60 bytes, otherwise are rejected as runts.
+ if (len < MIN_PACKET_LEN)
+ len = MIN_PACKET_LEN;
+
+ // Set transmit byte count registers to indicate packet length.
+ write_reg(TBCR0, len);
+ write_reg(TBCR1, 0u);
+
+ // Issue command for RTL8019AS to transmit packet from it's local buffer.
+ write_reg(CR, START | TXP);
+}
+
+void netdev_write_start(byte len)
+{
+ // Set remote DMA byte count registers to indicate length of packet load.
+ write_reg(RBCR0, len);
+ write_reg(RBCR1, 0u);
+
+ // Initiate DMA transfer of uip_buf & uip_appdata buffers to RTL8019AS.
+ write_reg(CR, WRITE);
+}
+
+void netdev_write_start_at(byte offset, byte len)
+{
+ // Set remote DMA start address registers to packet data.
+ write_reg(RSAR0, offset);
+ write_reg(RSAR1, TX_PAGE_START);