URL
https://opencores.org/ocsvn/xulalx25soc/xulalx25soc/trunk
Subversion Repositories xulalx25soc
[/] [xulalx25soc/] [trunk/] [rtl/] [wbscope.v] - Rev 72
Go to most recent revision | Compare with Previous | Blame | View Log
/////////////////////////////////////////////////////////////////////////// // // Filename: wbscope.v // // Project: FPGA Library of Routines // // Purpose: This is a generic/library routine for providing a bus accessed // 'scope' or (perhaps more appropriately) a bus accessed logic // analyzer. The general operation is such that this 'scope' can // record and report on any 32 bit value transiting through the // FPGA. Once started and reset, the scope records a copy of the // input data every time the clock ticks with the circuit enabled. // That is, it records these values up until the trigger. Once // the trigger goes high, the scope will record for bw_holdoff // more counts before stopping. Values may then be read from the // buffer, oldest to most recent. After reading, the scope may // then be reset for another run. // // In general, therefore, operation happens in this fashion: // 1. A reset is issued. // 2. Recording starts, in a circular buffer, and continues until // 3. The trigger line is asserted. // The scope registers the asserted trigger by setting // the 'o_triggered' output flag. // 4. A counter then ticks until the last value is written // The scope registers that it has stopped recording by // setting the 'o_stopped' output flag. // 5. The scope recording is then paused until the next reset. // 6. While stopped, the CPU can read the data from the scope // 7. -- oldest to most recent // 8. -- one value per i_rd&i_clk // 9. Writes to the data register reset the address to the // beginning of the buffer // // Although the data width DW is parameterized, it is not very changable, // since the width is tied to the width of the data bus, as is the // control word. Therefore changing the data width would require changing // the interface. It's doable, but it would be a change to the interface. // // The SYNCHRONOUS parameter turns on and off meta-stability // synchronization. Ideally a wishbone scope able to handle one or two // clocks would have a changing number of ports as this SYNCHRONOUS // parameter changed. Other than running another script to modify // this, I don't know how to do that so ... we'll just leave it running // off of two clocks or not. // // // Internal to this routine, registers and wires are named with one of the // following prefixes: // // i_ An input port to the routine // o_ An output port of the routine // br_ A register, controlled by the bus clock // dr_ A register, controlled by the data clock // bw_ A wire/net, controlled by the bus clock // dw_ A wire/net, controlled by the data clock // // Creator: Dan Gisselquist, Ph.D. // Gisselquist Technology, LLC // /////////////////////////////////////////////////////////////////////////// // // Copyright (C) 2015, Gisselquist Technology, LLC // // This program is free software (firmware): you can redistribute it and/or // modify it under the terms of the GNU General Public License as published // by the Free Software Foundation, either version 3 of the License, or (at // your option) any later version. // // This program is distributed in the hope that it will be useful, but WITHOUT // ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY or // FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License // for more details. // // You should have received a copy of the GNU General Public License along // with this program. (It's in the $(ROOT)/doc directory, run make with no // target there if the PDF file isn't present.) If not, see // <http://www.gnu.org/licenses/> for a copy. // // License: GPL, v3, as defined and found on www.gnu.org, // http://www.gnu.org/licenses/gpl.html // // ///////////////////////////////////////////////////////////////////////////// module wbscope(i_clk, i_ce, i_trigger, i_data, i_wb_clk, i_wb_cyc, i_wb_stb, i_wb_we, i_wb_addr, i_wb_data, o_wb_ack, o_wb_stall, o_wb_data, o_interrupt); parameter LGMEM = 5'd10, BUSW = 32, SYNCHRONOUS=1; // The input signals that we wish to record input i_clk, i_ce, i_trigger; input [(BUSW-1):0] i_data; // The WISHBONE bus for reading and configuring this scope input i_wb_clk, i_wb_cyc, i_wb_stb, i_wb_we; input i_wb_addr; // One address line only input [(BUSW-1):0] i_wb_data; output wire o_wb_ack, o_wb_stall; output reg [(BUSW-1):0] o_wb_data; // And, finally, for a final flair --- offer to interrupt the CPU after // our trigger has gone off. This line is equivalent to the scope // being stopped. It is not maskable here. output wire o_interrupt; reg [(LGMEM-1):0] raddr; reg [(BUSW-1):0] mem[0:((1<<LGMEM)-1)]; // Our status/config register wire bw_reset_request, bw_manual_trigger, bw_disable_trigger, bw_reset_complete; reg [22:0] br_config; wire [19:0] bw_holdoff; initial br_config = ((1<<(LGMEM-1))-4); always @(posedge i_wb_clk) if ((i_wb_cyc)&&(i_wb_stb)&&(~i_wb_addr)) begin if (i_wb_we) br_config <= { i_wb_data[31], (i_wb_data[27]), i_wb_data[26], i_wb_data[19:0] }; end else if (bw_reset_complete) br_config[22] <= 1'b1; assign bw_reset_request = (~br_config[22]); assign bw_manual_trigger = (br_config[21]); assign bw_disable_trigger = (br_config[20]); assign bw_holdoff = br_config[19:0]; wire dw_reset, dw_manual_trigger, dw_disable_trigger; generate if (SYNCHRONOUS > 0) begin assign dw_reset = bw_reset_request; assign dw_manual_trigger = bw_manual_trigger; assign dw_disable_trigger = bw_disable_trigger; assign bw_reset_complete = bw_reset_request; end else begin reg r_reset_complete; reg [2:0] r_iflags, q_iflags; // Resets are synchronous to the bus clock, not the data clock // so do a clock transfer here initial q_iflags = 3'b000; initial r_reset_complete = 1'b0; always @(posedge i_clk) begin q_iflags <= { bw_reset_request, bw_manual_trigger, bw_disable_trigger }; r_iflags <= q_iflags; r_reset_complete <= (dw_reset); end assign dw_reset = r_iflags[2]; assign dw_manual_trigger = r_iflags[1]; assign dw_disable_trigger = r_iflags[0]; reg q_reset_complete, qq_reset_complete; // Pass an acknowledgement back from the data clock to the bus // clock that the reset has been accomplished initial q_reset_complete = 1'b0; initial qq_reset_complete = 1'b0; always @(posedge i_wb_clk) begin q_reset_complete <= r_reset_complete; qq_reset_complete <= q_reset_complete; end assign bw_reset_complete = qq_reset_complete; end endgenerate // // Set up the trigger // // // Write with the i-clk, or input clock. All outputs read with the // WISHBONE-clk, or i_wb_clk clock. reg dr_triggered, dr_primed; wire dw_trigger; assign dw_trigger = (dr_primed)&&( ((i_trigger)&&(~dw_disable_trigger)) ||(dr_triggered) ||(dw_manual_trigger)); initial dr_triggered = 1'b0; always @(posedge i_clk) if (dw_reset) dr_triggered <= 1'b0; else if ((i_ce)&&(dw_trigger)) dr_triggered <= 1'b1; // // Determine when memory is full and capture is complete // // Writes take place on the data clock reg dr_stopped; reg [19:0] counter; // This is unsigned initial dr_stopped = 1'b0; initial counter = 20'h0000; always @(posedge i_clk) if (dw_reset) begin counter <= 0; dr_stopped <= 1'b0; end else if ((i_ce)&&(dr_triggered)) begin // MUST BE a < and not <=, so that we can keep this w/in // 20 bits. Else we'd need to add a bit to comparison // here. if (counter < bw_holdoff) counter <= counter + 20'h01; else dr_stopped <= 1'b1; end // // Actually do our writes to memory. Record, via 'primed' when // the memory is full. // // The 'waddr' address that we are using really crosses two clock // domains. While writing and changing, it's in the data clock // domain. Once stopped, it becomes part of the bus clock domain. // The clock transfer on the stopped line handles the clock // transfer for these signals. // reg [(LGMEM-1):0] waddr; initial waddr = {(LGMEM){1'b0}}; initial dr_primed = 1'b0; always @(posedge i_clk) if (dw_reset) // For simulation purposes, supply a valid value begin waddr <= 0; // upon reset. dr_primed <= 1'b0; end else if ((i_ce)&&((~dr_triggered)||(counter < bw_holdoff))) begin // mem[waddr] <= i_data; waddr <= waddr + {{(LGMEM-1){1'b0}},1'b1}; dr_primed <= (dr_primed)||(&waddr); end always @(posedge i_clk) if ((i_ce)&&((~dr_triggered)||(counter < bw_holdoff))) mem[waddr] <= i_data; // // Clock transfer of the status signals // wire bw_stopped, bw_triggered, bw_primed; generate if (SYNCHRONOUS > 0) begin assign bw_stopped = dr_stopped; assign bw_triggered = dr_triggered; assign bw_primed = dr_primed; end else begin // These aren't a problem, since none of these are strobe // signals. They goes from low to high, and then stays high // for many clocks. Swapping is thus easy--two flip flops to // protect against meta-stability and we're done. // reg [2:0] q_oflags, r_oflags; initial q_oflags = 3'h0; initial r_oflags = 3'h0; always @(posedge i_wb_clk) if (bw_reset_request) begin q_oflags <= 3'h0; r_oflags <= 3'h0; end else begin q_oflags <= { dr_stopped, dr_triggered, dr_primed }; r_oflags <= q_oflags; end assign bw_stopped = r_oflags[2]; assign bw_triggered = r_oflags[1]; assign bw_primed = r_oflags[0]; end endgenerate // Reads use the bus clock reg br_wb_ack; initial br_wb_ack = 1'b0; wire bw_cyc_stb; assign bw_cyc_stb = ((i_wb_cyc)&&(i_wb_stb)); always @(posedge i_wb_clk) begin if ((bw_reset_request) ||((bw_cyc_stb)&&(i_wb_addr)&&(i_wb_we))) raddr <= 0; else if ((bw_cyc_stb)&&(i_wb_addr)&&(~i_wb_we)&&(bw_stopped)) raddr <= raddr + {{(LGMEM-1){1'b0}},1'b1}; // Data read, when stopped if ((bw_cyc_stb)&&(~i_wb_we)) begin // Read from the bus br_wb_ack <= 1'b1; end else if ((bw_cyc_stb)&&(i_wb_we)) // We did this write above br_wb_ack <= 1'b1; else // Do nothing if either i_wb_cyc or i_wb_stb are low br_wb_ack <= 1'b0; end reg [31:0] nxt_mem; always @(posedge i_wb_clk) nxt_mem <= mem[raddr+waddr+ (((bw_cyc_stb)&&(i_wb_addr)&&(~i_wb_we)) ? {{(LGMEM-1){1'b0}},1'b1} : { (LGMEM){1'b0}} )]; wire [4:0] bw_lgmem; assign bw_lgmem = LGMEM; always @(posedge i_wb_clk) if (~i_wb_addr) // Control register read o_wb_data <= { bw_reset_request, bw_stopped, bw_triggered, bw_primed, bw_manual_trigger, bw_disable_trigger, (raddr == {(LGMEM){1'b0}}), bw_lgmem, bw_holdoff }; else if (~bw_stopped) // read, prior to stopping o_wb_data <= i_data; else // if (i_wb_addr) // Read from FIFO memory o_wb_data <= nxt_mem; // mem[raddr+waddr]; assign o_wb_stall = 1'b0; assign o_wb_ack = (i_wb_cyc)&&(br_wb_ack); reg br_level_interrupt; initial br_level_interrupt = 1'b0; assign o_interrupt = (bw_stopped)&&(~bw_disable_trigger) &&(~br_level_interrupt); always @(posedge i_wb_clk) if ((bw_reset_complete)||(bw_reset_request)) br_level_interrupt<= 1'b0; else br_level_interrupt<= (bw_stopped)&&(~bw_disable_trigger); endmodule
Go to most recent revision | Compare with Previous | Blame | View Log