Create UART and uart_wrapper

hw/efinix_fpga/uart_wrapper.sv

@@ -0,0 +1,106 @@
+module uart_wrapper(
+    input clk,
+    input clk_50,
+    input reset,
+    input [7:0] i_data,
+    output logic [7:0] o_data,
+    input cs,
+    input rwb,
+    input addr,
+
+    input rx_i,
+    output tx_o,
+
+    output logic irqb
+);
+
+logic status, control;
+
+logic tx_busy, rx_busy;
+
+logic rx_data_valid, rx_error, rx_parity_error;
+logic baud_x16_ce;
+
+logic tx_en;
+
+logic [7:0] tx_data, rx_data;
+
+uart u_uart(
+    .tx_o ( tx_o ),
+    .rx_i ( rx_i ),
+    .tx_busy ( tx_busy ),
+    .rx_data ( rx_data ),
+    .rx_data_valid ( rx_data_valid ),
+    .rx_error ( rx_error ),
+    .rx_parity_error ( rx_parity_error ),
+    .rx_busy ( rx_busy ),
+    .baud_x16_ce ( baud_x16_ce ),
+    .clk ( clk_50 ),
+    .reset ( reset ),
+    .tx_data ( tx_data ),
+    .baud_rate ( baud_rate ),
+    .tx_en ( tx_en )
+);
+
+enum bit [1:0] {READY, WAIT, TRANSMIT} state, next_state;
+
+always_ff @(negedge clk) begin
+    if (reset) begin
+        state = READY;
+        irqb <= '1;
+    end else begin
+        state <= next_state;
+    end
+
+    case (addr)
+        1'b0: begin
+            tx_data <= i_data;
+        end 
+
+        1'b1: begin
+            control <= i_data;
+        end
+    endcase
+
+end
+
+always_comb begin
+    case (addr)
+        1'b0: begin
+            o_data = rx_data;
+        end 
+
+        1'b1: begin
+            o_data = status;
+        end
+    endcase
+end
+
+always_comb begin
+    next_state = state;
+
+    tx_en = 1'b0;
+
+    case (state)
+        READY: begin
+            if (~rwb && addr == 1'b0) begin //write to transmit
+                tx_en = 1'b1;
+                next_state = WAIT;
+            end
+        end
+
+        WAIT: begin
+            if (tx_busy) begin
+                next_state = TRANSMIT;
+            end
+        end
+
+        TRANSMIT: begin
+            if (~tx_busy) begin
+                next_state = READY;
+            end
+        end
+    endcase
+end
+
+endmodule