FreeCalypso > hg > fc-sim-sniff
view fpga/sniffer-basic/uart_tx.v @ 48:1068f9fd41d5
doc: project rename
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Thu, 21 Sep 2023 06:31:34 +0000 |
parents | 7db5fd6646df |
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/* * This Verilog module captures the UART output logic. */ module uart_tx (IntClk, Tx_trigger, Tx_data, UART_out); input IntClk; input Tx_trigger; input [15:0] Tx_data; output UART_out; reg UART_out; reg tx_active; reg [1:0] clk_div; reg [4:0] bit_count; reg [17:0] shift_reg; initial begin tx_active = 1'b0; UART_out = 1'b1; end always @(posedge IntClk) if (!tx_active && Tx_trigger) begin tx_active <= 1'b1; UART_out <= 1'b0; clk_div <= 2'd0; shift_reg <= {Tx_data[15:8],2'b01,Tx_data[7:0]}; bit_count <= 5'd0; end else if (tx_active) begin clk_div <= clk_div + 2'd1; if (clk_div == 2'd3) begin UART_out <= shift_reg[0]; shift_reg <= {1,shift_reg[17:1]}; bit_count <= bit_count + 5'd1; if (bit_count == 5'd19) tx_active <= 1'b0; end end endmodule