diff --git a/library/altera/avl_dacfifo/avl_dacfifo.v b/library/altera/avl_dacfifo/avl_dacfifo.v index c22a9aee4..de2e2c0d1 100644 --- a/library/altera/avl_dacfifo/avl_dacfifo.v +++ b/library/altera/avl_dacfifo/avl_dacfifo.v @@ -49,7 +49,7 @@ module avl_dacfifo #( input dac_valid, output reg [(DAC_DATA_WIDTH-1):0] dac_data, output reg dac_dunf, - output reg dac_xfer_out, + output dac_xfer_out, input bypass, @@ -77,6 +77,7 @@ module avl_dacfifo #( reg dac_bypass_m1 = 1'b0; reg dac_bypass = 1'b0; reg dac_xfer_out_m1 = 1'b0; + reg dac_xfer_out_int = 1'b0; reg dac_xfer_out_bypass = 1'b0; reg avl_xfer_wren = 1'b0; reg avl_dma_xfer_req = 1'b0; @@ -238,7 +239,7 @@ module avl_dacfifo #( if (dac_valid) begin dac_data <= (dac_bypass) ? dac_data_bypass_s : dac_data_fifo_s; end - dac_xfer_out <= (dac_bypass) ? dac_xfer_out_bypass : dac_xfer_fifo_out_s; + dac_xfer_out_int <= (dac_bypass) ? dac_xfer_out_bypass : dac_xfer_fifo_out_s; dac_dunf <= (dac_bypass) ? dac_dunf_bypass_s : dac_dunf_fifo_s; end @@ -251,13 +252,28 @@ module avl_dacfifo #( if (dac_valid) begin dac_data <= dac_data_fifo_s; end - dac_xfer_out <= dac_xfer_fifo_out_s; + dac_xfer_out_int <= dac_xfer_fifo_out_s; dac_dunf <= dac_dunf_fifo_s; end end endgenerate + // the ad_mem_asym memory read interface has a 3 clock cycle delay, from the + // moment of the address change until a valid data arrives on the bus; + // because the dac_xfer_out is going to validate the outgoing samples (in conjunction + // with the DAC VALID, which is free a running signal), this module will compensate + // this delay, to prevent duplicated samples in the beginning of the + // transaction + + util_delay #( + .DATA_WIDTH(1), + .DELAY_CYCLES(3) + ) i_delay ( + .clk(dac_clk), + .reset(dac_reset), + .din(dac_xfer_out_int), + .dout(dac_xfer_out)); endmodule diff --git a/library/altera/avl_dacfifo/avl_dacfifo_hw.tcl b/library/altera/avl_dacfifo/avl_dacfifo_hw.tcl index 653568a3c..257bd4dee 100644 --- a/library/altera/avl_dacfifo/avl_dacfifo_hw.tcl +++ b/library/altera/avl_dacfifo/avl_dacfifo_hw.tcl @@ -7,6 +7,7 @@ ad_ip_create avl_dacfifo {Avalon DDR DAC Fifo} ad_ip_files avl_dacfifo [list\ $ad_hdl_dir/library/altera/common/ad_mem_asym.v \ $ad_hdl_dir/library/common/util_dacfifo_bypass.v \ + $ad_hdl_dir/library/common/util_delay.v \ avl_dacfifo_wr.v \ avl_dacfifo_rd.v \ avl_dacfifo.v \