FreeCalypso > hg > fc-pcm-if
diff fpga/mcsi-rx/uart_tx.v @ 1:b3190839cce3
first FPGA version, MCSI Rx only
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Fri, 11 Oct 2024 21:11:24 +0000 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/fpga/mcsi-rx/uart_tx.v Fri Oct 11 21:11:24 2024 +0000 @@ -0,0 +1,45 @@ +/* + * 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 [5:0] 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 <= 6'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 + 6'd1; + if (clk_div == 6'd63) + 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