blob: 0f477ad485d16381f61b892d388098cf117a598a [file] [log] [blame]
`default_nettype none
/*
`ifdef COCOTB
`define UNIT_DELAY #1
`define FUNCTIONAL
`define USE_POWER_PINS
`include "libs.ref/sky130_fd_sc_hd/verilog/primitives.v"
`include "libs.ref/sky130_fd_sc_hd/verilog/sky130_fd_sc_hd.v"
`endif
*/
module scan_wrapper_341426151397261906 (
input wire clk_in,
input wire data_in,
input wire scan_select_in,
input wire latch_enable_in,
output wire clk_out,
output wire data_out,
output wire scan_select_out,
output wire latch_enable_out
);
// input buffers
// Looking at results from multiple projects the bufferring is a bit
// inconsistent. So instead, we ensure at least clk buf
wire clk;
sky130_fd_sc_hd__clkbuf_2 input_buf_clk (
`ifdef WITH_POWER
.VPWR (1'b1),
.VGND (1'b0),
`endif
.A (clk_in),
.X (clk)
);
// We disable the resizer, so buffer input like it is done
// when the resizer does it for us
wire data_in_i;
wire scan_select_in_i;
wire latch_enable_in_i;
sky130_fd_sc_hd__buf_2 input_buffers[2:0] (
`ifdef WITH_POWER
.VPWR (1'b1),
.VGND (1'b0),
`endif
.A ({data_in, scan_select_in, latch_enable_in }),
.X ({data_in_i, scan_select_in_i, latch_enable_in_i })
);
// output buffers
// Same as for input, to try and be more consistent, we make our own
wire data_out_i;
sky130_fd_sc_hd__buf_4 output_buffers[3:0] (
`ifdef WITH_POWER
.VPWR (1'b1),
.VGND (1'b0),
`endif
.A ({clk, data_out_i, scan_select_in_i, latch_enable_in_i }),
.X ({clk_out, data_out, scan_select_out, latch_enable_out })
);
/*
`ifdef COCOTB
initial begin
$dumpfile ("scan_wrapper.vcd");
$dumpvars (0, scan_wrapper_lesson_1);
#1;
end
`endif
*/
parameter NUM_IOS = 8;
// wires needed
wire [NUM_IOS-1:0] scan_data_out; // output of the each scan chain flop
wire [NUM_IOS-1:0] scan_data_in; // input of each scan chain flop
wire [NUM_IOS-1:0] module_data_in; // the data that enters the user module
wire [NUM_IOS-1:0] module_data_out; // the data from the user module
// scan chain - link all the flops, with data coming from data_in
assign scan_data_in = {scan_data_out[NUM_IOS-2:0], data_in_i};
// end of the chain is a negedge FF to increase hold margin between blocks
sky130_fd_sc_hd__dfrtn_1 out_flop (
`ifdef WITH_POWER
.VPWR (1'b1),
.VGND (1'b0),
`endif
.RESET_B (1'b1),
.CLK_N (clk),
.D (scan_data_out[NUM_IOS-1]),
.Q (data_out_i)
);
// scan flops have a mux on their inputs to choose either data from the user module or the previous flop's output
// https://antmicro-skywater-pdk-docs.readthedocs.io/en/test-submodules-in-rtd/contents/libraries/sky130_fd_sc_ls/cells/sdfxtp/README.html
`ifndef FORMAL
`ifndef FORMAL_COMPAT
sky130_fd_sc_hd__sdfxtp_1 scan_flop [NUM_IOS-1:0] (
`ifdef WITH_POWER
.VPWR (1'b1),
.VGND (1'b0),
`endif
.CLK (clk),
.D (scan_data_in),
.SCD (module_data_out),
.SCE (scan_select_in_i),
.Q (scan_data_out)
);
`endif
`endif
// Send output of scan chain directly
assign module_data_in = scan_data_out;
// instantiate the wokwi module
user_module_341426151397261906 user_module(
.latch_in (latch_enable_in_i),
.io_in (module_data_in),
.io_out (module_data_out)
);
endmodule