diff options
Diffstat (limited to 'rtl/src/verilog/eim_arbiter_cdc.v')
| -rw-r--r-- | rtl/src/verilog/eim_arbiter_cdc.v | 200 |
1 files changed, 98 insertions, 102 deletions
diff --git a/rtl/src/verilog/eim_arbiter_cdc.v b/rtl/src/verilog/eim_arbiter_cdc.v index a0412fe..15dc433 100644 --- a/rtl/src/verilog/eim_arbiter_cdc.v +++ b/rtl/src/verilog/eim_arbiter_cdc.v @@ -7,7 +7,7 @@ // // // Author: Pavel Shatov -// Copyright (c) 2014, NORDUnet A/S All rights reserved. +// Copyright (c) 2015, NORDUnet A/S All rights reserved. // // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions @@ -38,107 +38,103 @@ //====================================================================== module eim_arbiter_cdc - ( - eim_clk, eim_req, eim_ack, eim_din, eim_dout, - sys_clk, sys_addr, - sys_wren, sys_data_out, - sys_rden, sys_data_in - ); - - - input wire eim_clk; // eim clock - input wire eim_req; // eim transaction request - output wire eim_ack; // eim transaction acknowledge - input wire [50: 0] eim_din; // data from cpu to fpga (write access) - output wire [31: 0] eim_dout; // data from fpga to cpu (read access) - - input wire sys_clk; // user internal clock - output wire [16: 0] sys_addr; // user access address - output wire sys_wren; // user write flag - output wire [31: 0] sys_data_out; // user write data - output wire sys_rden; // user read flag - input wire [31: 0] sys_data_in; // user read data - - - // - // EIM_CLK -> SYS_CLK Request - // - wire sys_req; // request pulse in sys_clk clock domain - wire [50: 0] sys_dout; // transaction data in sys_clk clock domain - - cdc_bus_pulse # - ( - .DATA_WIDTH (51) // {write, read, msb addr, lsb addr, data} - ) - cdc_eim_sys - ( - .src_clk (eim_clk), - .src_din (eim_din), - .src_req (eim_req), - - .dst_clk (sys_clk), - .dst_dout (sys_dout), - .dst_pulse (sys_req) - ); - - - // - // Output Registers - // - reg sys_wren_reg = 1'b0; //
- reg sys_rden_reg = 1'b0; //
- reg [16: 0] sys_addr_reg = {17{1'bX}}; // - reg [31: 0] sys_data_out_reg = {32{1'bX}}; // -
- assign sys_wren = sys_wren_reg;
- assign sys_rden = sys_rden_reg; - assign sys_addr = sys_addr_reg; - assign sys_data_out = sys_data_out_reg; - - - // - // System (User) Clock Access Handler - // - always @(posedge sys_clk) - // - if (sys_req) begin // request detected? - sys_wren_reg <= sys_dout[50]; // set write flag if needed
- sys_rden_reg <= sys_dout[49]; // set read flag if needed - sys_addr_reg <= sys_dout[48:32]; // set operation address - sys_data_out_reg <= sys_dout[31: 0]; // set data to write - end else begin // no request active - sys_wren_reg <= 1'b0; // clear write flag - sys_rden_reg <= 1'b0; // clear read flag - end - - - // - // System Request 2-cycle delay to compensate registered mux delay in user-side logic - // - reg [ 1: 0] sys_req_dly = 2'b00; - - always @(posedge sys_clk) - sys_req_dly <= {sys_req_dly[0], sys_req}; - - - // - // SYS_CLK -> EIM_CLK Acknowledge - // - cdc_bus_pulse # - ( - .DATA_WIDTH (32) // {data} - ) - cdc_sys_eim - ( - .src_clk (sys_clk), - .src_din (sys_data_in), - .src_req (sys_req_dly[1]), - - .dst_clk (eim_clk), - .dst_dout (eim_dout), - .dst_pulse (eim_ack) - ); - + ( + input wire eim_clk, // eim clock + input wire eim_req, // eim transaction request + output wire eim_ack, // eim transaction acknowledge + input wire [50: 0] eim_din, // data from cpu to fpga (write access) + output wire [31: 0] eim_dout, // data from fpga to cpu (read access) + + input wire sys_clk, // user internal clock + output wire [16: 0] sys_addr, // user access address + output wire sys_wren, // user write flag + output wire [31: 0] sys_data_out, // user write data + output wire sys_rden, // user read flag + input wire [31: 0] sys_data_in // user read data + ); + + + // + // EIM_CLK -> SYS_CLK Request + // + wire sys_req; // request pulse in sys_clk clock domain + wire [50: 0] sys_dout; // transaction data in sys_clk clock domain + + cdc_bus_pulse # + ( + .DATA_WIDTH(51) // {write, read, msb addr, lsb addr, data} + ) + cdc_eim_sys + ( + .src_clk(eim_clk), + .src_din(eim_din), + .src_req(eim_req), + + .dst_clk(sys_clk), + .dst_dout(sys_dout), + .dst_pulse(sys_req) + ); + + + // + // Output Registers + // + reg sys_wren_reg = 1'b0; + reg sys_rden_reg = 1'b0; + reg [16: 0] sys_addr_reg = {17{1'bX}}; + reg [31: 0] sys_data_out_reg = {32{1'bX}}; + + assign sys_wren = sys_wren_reg; + assign sys_rden = sys_rden_reg; + assign sys_addr = sys_addr_reg; + assign sys_data_out = sys_data_out_reg; + + + // + // System (User) Clock Access Handler + // + always @(posedge sys_clk) + // + if (sys_req) // request detected? + begin + sys_wren_reg <= sys_dout[50]; // set write flag if needed + sys_rden_reg <= sys_dout[49]; // set read flag if needed + sys_addr_reg <= sys_dout[48:32]; // set operation address + sys_data_out_reg <= sys_dout[31: 0]; // set data to write + end + else // no request active + begin + sys_wren_reg <= 1'b0; // clear write flag + sys_rden_reg <= 1'b0; // clear read flag + end + + + // + // System Request 2-cycle delay to compensate registered mux delay in user-side logic + // + reg [ 1: 0] sys_req_dly = 2'b00; + + always @(posedge sys_clk) + sys_req_dly <= {sys_req_dly[0], sys_req}; + + + // + // SYS_CLK -> EIM_CLK Acknowledge + // + cdc_bus_pulse # + ( + .DATA_WIDTH(32) + ) + cdc_sys_eim + ( + .src_clk(sys_clk), + .src_din(sys_data_in), + .src_req(sys_req_dly[1]), + + .dst_clk(eim_clk), + .dst_dout(eim_dout), + .dst_pulse(eim_ack) + ); endmodule |