diff options
Diffstat (limited to 'fpga/usrp2/gpmc/gpmc.v')
| -rw-r--r-- | fpga/usrp2/gpmc/gpmc.v | 39 |
1 files changed, 38 insertions, 1 deletions
diff --git a/fpga/usrp2/gpmc/gpmc.v b/fpga/usrp2/gpmc/gpmc.v index a5d4db466..8ecae4daf 100644 --- a/fpga/usrp2/gpmc/gpmc.v +++ b/fpga/usrp2/gpmc/gpmc.v @@ -49,6 +49,18 @@ module gpmc wire [15:0] EM_D_fifo; wire [15:0] EM_D_wb; + // these registers are used for the GPMC-to-FIFO interface + reg [15:0] em_d_reg; + reg [ADDR_WIDTH:1] em_a_reg; + reg [1:0] em_nbe_reg; + reg em_wait0_reg; + reg em_ncs4_reg; + reg em_ncs6_reg; + reg em_nwe_reg; + reg em_noe_reg; + + + assign EM_D = ~EM_output_enable ? 16'bz : ~EM_NCS4 ? EM_D_fifo : EM_D_wb; // CS4 is RAM_2PORT for DATA PATH (high-speed data) @@ -63,9 +75,34 @@ module gpmc wire [35:0] tx_data, txb_data; wire tx_src_rdy, tx_dst_rdy; wire txb_src_rdy, txb_dst_rdy; + + // Register signals to prevent Sequence errors (S-errors) from occuring + always @(negedge EM_CLK or posedge arst) begin + if (arst) begin + + em_d_reg <= 0; + em_a_reg <= 0; + em_nbe_reg <= 0; + em_wait0_reg <= 0; + em_ncs4_reg <= 0; + em_ncs6_reg <= 0; + em_nwe_reg <= 0; + em_noe_reg <= 0; + end + else begin + em_d_reg <= EM_D; + em_a_reg <= EM_A; + em_nbe_reg <= EM_NBE; + em_wait0_reg <= EM_WAIT0; + em_ncs4_reg <= EM_NCS4; + em_ncs6_reg <= EM_NCS6; + em_nwe_reg <= EM_NWE; + em_noe_reg <= EM_NOE; + end + end gpmc_to_fifo #(.ADDR_WIDTH(ADDR_WIDTH)) gpmc_to_fifo - (.EM_D(EM_D), .EM_A(EM_A), .EM_CLK(EM_CLK), .EM_WE(~EM_NCS4 & ~EM_NWE), + (.EM_D(em_d_reg), .EM_A(em_a_reg), .EM_CLK(EM_CLK), .EM_WE(~em_ncs4_reg & ~em_nwe_reg), .clk(fifo_clk), .reset(fifo_rst), .clear(clear_tx), .arst(fifo_rst | clear_tx | arst), .data_o(tx18_data), .src_rdy_o(tx18_src_rdy), .dst_rdy_i(tx18_dst_rdy), .have_space(tx_have_space)); |