blob: 5755d1864b299a4ed44f0fdba26349776578361b [file] [log] [blame]
`default_nettype none
module wb_led(
`ifdef USE_POWER_PINS
inout vccd1, // User area 1 1.8V supply
inout vssd1, // User area 1 digital ground
`endif
// RCC
input wire i_clk,
input wire i_reset,
// Output
output reg o_led,
// Wishbone
input wire [31:0] i_wb_adr,
input wire [31:0] i_wb_dat,
input wire [3:0] i_wb_sel,
input wire i_wb_we,
input wire i_wb_cyc,
input wire i_wb_stb,
output reg [31:0] o_wb_dat,
output reg o_wb_ack
);
// Wishbone register addresses
localparam
wb_r_DATA = 1'b0,
wb_r_MAX = 1'b1;
// register
reg [31:0] data;
// output generation
always @(posedge i_clk) begin
o_led <= data[0];
end
// Since the incoming wishbone address from the CPU increments by 4 bytes, we
// need to right shift it by 2 to get our actual register index
localparam reg_sel_bits = $clog2(wb_r_MAX + 1);
wire [reg_sel_bits-1:0] register_index = i_wb_adr[reg_sel_bits+1:2];
always @(posedge i_clk) begin
if (i_reset) begin
o_wb_ack <= 0;
data <= 0;
end else begin
// Wishbone interface logic
o_wb_ack <= 1'b0;
if (i_wb_cyc && i_wb_stb && !o_wb_ack) begin
o_wb_ack <= 1'b1;
// Register read
case (register_index)
wb_r_DATA: o_wb_dat <= data;
endcase
// Register write
if (i_wb_we) begin
case (register_index)
wb_r_DATA: data <= i_wb_dat;
endcase
end
end
end
end
endmodule