altddio_out in Cyclone III FPGA Development Kit

Hello!

I encountered the following problem. When you try to transmit data over Ethernet in 1000, the output is constantly 0.

I use to break altddio_out to break feed stream 8-bit words in the 4-bit. Connected as follows:

altddio_out diff_out(

.datain_h(MAC_out[7:4]),

.datain_l(MAC_out[3:0]),

.outclock(enet_gtx_clk),

.dataout(ddr_out)

);

wire [3:0] ddr_out;

top top (

.enet_tx_d(ddr_out),

.enet_tx_dv(MAC_out_v_del),

.enet_gtx(enet_gtx_clk),

.....

);

enet_tx_d always = 0;

How fix it?