Copy modify and learn of the exemple code for uart on tang nano 20k

Semaine 1/UARTV2/tb_top_uart_rx_tx.v

@@ -0,0 +1,69 @@
+`timescale 1ns / 1ps
+
+module tb_top_uart_rx_tx;
+
+    parameter CLK_FREQ = 27_000_000;
+    parameter BAUD_RATE = 115200;
+
+    // Signaux
+    reg clk = 0;
+    reg start = 0;
+    reg [7:0] data_in = 0;
+    wire [7:0] data_out;
+    wire valid;
+    wire tx;
+    wire rx;  // On connecte tx directement à rx pour le test
+
+    // Instance du module à tester
+    top_uart_rx_tx #(
+        .CLK_FREQ(CLK_FREQ),
+        .BAUD_RATE(BAUD_RATE)
+    ) uut (
+        .clk(clk),
+        .start(start),
+        .data_in(data_in),
+        .rx(rx),
+        .data_out(data_out),
+        .valid(valid),
+        .tx(tx)
+    );
+
+    // Boucle le tx sur rx
+    assign rx = tx;
+
+    // Clock à 50 MHz (20 ns période)
+    always #10 clk = ~clk;
+
+    // Simulation principale
+    initial begin
+        $display("Début de la simulation");
+        $dumpfile("uart_loopback.vcd"); // Pour GTKWave
+        $dumpvars(0, tb_top_uart_rx_tx);
+
+        // Attendre un peu
+        #(20 * 10);
+
+        // Envoi d'une valeur
+        data_in = 8'hA5;  // Exemple de data
+        start = 1;
+        #20;
+        start = 0;
+
+        // Attendre la réception (valeur valid = 1)
+        wait(valid == 1);
+
+        // Affichage des résultats
+        $display("Data envoyee : 0x%h", data_in);
+        $display("Data recue   : 0x%h", data_out);
+
+        if (data_out == data_in)
+            $display("Test reussi !");
+        else
+            $display("Test echoue...");
+
+        // Fin de simulation
+        #(20 * 10);
+        $finish;
+    end
+
+endmodule

Semaine 1/UARTV2/tb_uart_rx.v

@@ -0,0 +1,64 @@
+`timescale 1ns / 1ps
+
+module tb_uart_rx;
+
+    reg clk = 0;
+    reg rx = 1;  
+    wire [7:0] data;
+    wire valid;
+    wire ready;
+
+    localparam CLK_FREQ = 27_000_000;
+    localparam BAUD_RATE = 115_200;
+    localparam BIT_PERIOD = CLK_FREQ / BAUD_RATE; 
+    localparam CLK_PERIOD_NS = 1000000000 / CLK_FREQ; 
+
+    uart_rx #(
+        .CLK_FREQ(CLK_FREQ),
+        .BAUD_RATE(BAUD_RATE)
+    ) rx_instance (
+        .clk(clk),
+        .rx(rx),
+        .data(data),
+        .valid(valid),
+        .ready(ready)
+    );
+
+    always #(CLK_PERIOD_NS/2) clk = ~clk;
+
+    task send_bit(input reg b);
+        begin
+            rx <= b;
+            #(BIT_PERIOD * CLK_PERIOD_NS); 
+        end
+    endtask
+
+    integer i;
+
+    task send_byte(input [7:0] byte);
+        begin
+            send_bit(0); 
+            for (i = 0; i < 8; i = i + 1)
+                send_bit(byte[i]); 
+            send_bit(1); 
+            
+            #(BIT_PERIOD * CLK_PERIOD_NS);
+        end
+    endtask
+
+    initial begin
+        $display("Start UART RX test");
+        #100; 
+
+        send_byte(8'b01010101); 
+
+        #(10 * BIT_PERIOD * CLK_PERIOD_NS);
+
+        if (valid && data == 8'b01010101)
+            $display("Test ok : data = %b", data);
+        else
+            $display("Test pas ok : data = %b, valid = %b", data, valid);
+
+        $finish;
+    end
+endmodule

Semaine 1/UARTV2/tb_uart_tx.v

@@ -0,0 +1,49 @@
+`timescale 1ns/1ps
+
+module tb_uart_tx;
+
+    reg clk = 0;
+    reg start = 0;
+    reg [7:0] data = 8'h00;
+    wire tx;
+    wire busy;
+
+    always #18.5 clk = ~clk;
+
+    uart_tx #(
+        .CLK_FREQ(27_000_000),
+        .BAUD_RATE(115_200)
+    )tx_instance (
+        .clk(clk),
+        .start(start),
+        .data(data),
+        .tx(tx),
+        .busy(busy)
+    );
+
+    initial begin
+        $dumpfile("uart_tx.vcd");
+        $dumpvars(0, tb_uart_tx);
+
+        #100;
+
+        data <= 8'hA5;   // 10100101 0xA5
+        start <= 1;
+        #37 start <= 0; 
+
+        // Attendre
+        wait (busy == 0);
+
+        #1000;
+
+        data <= 8'h3C;   // 00111100  0x3C
+        start <= 1;
+        #37 start <= 0;
+
+        wait (busy == 0);
+
+        #1000;
+        $stop;
+    end
+
+endmodule

Semaine 1/UARTV2/top_led_uart.v

@@ -0,0 +1,61 @@
+module top_led_uart(
+    input wire clk,
+    input wire rx,
+    output wire tx,
+    output reg [5:0] leds
+);
+    wire [7:0] data_out;
+    wire valid;
+    reg start_tx = 0;
+    reg [7:0] data_in = 0;
+
+    top_uart_rx_tx uart (
+        .clk(clk),
+        .start(start_tx),
+        .data_in(data_in),
+        .rx(rx),
+        .data_out(data_out),
+        .valid(valid),
+        .tx(tx)
+    );
+
+    reg [1:0] state = 0;
+    localparam IDLE = 2'd0;
+    localparam TOGGLE = 2'd1;
+    localparam SEND_BACK = 2'd2;
+
+    always @(posedge clk) begin
+        case (state)
+            INIT: begin
+                leds <= 6'b000000; 
+                start_tx <= 0;
+                if (valid) begin
+                    
+                    leds <= data_out[5:0];
+                    state <= SEND_BACK;
+                    
+                end
+            end
+            IDLE: begin
+                start_tx <= 0;
+                if (valid) begin
+                    
+                    leds <= data_out[5:0];
+                    state <= SEND_BACK;
+                    
+                end
+            end
+
+            SEND_BACK: begin
+                data_in <= data_out;
+                start_tx <= 1;
+                state <= TOGGLE;
+            end
+
+            TOGGLE: begin
+                start_tx <= 0;
+                state <= IDLE;
+            end
+        endcase
+    end
+endmodule

Semaine 1/UARTV2/top_uart_rx_tx.v

@@ -0,0 +1,119 @@
+module uart_top(
+	input                        clk,
+	input                        rst,
+	input                        uart_rx,
+	output                       uart_tx
+);
+
+parameter                        CLK_FRE  = 27_000_000; // Mhz
+parameter                        UART_FRE = 115200;     // Baud
+
+localparam                       IDLE =  0;
+localparam                       SEND =  1;   // send 
+localparam                       WAIT =  2;   // wait 1 second and send uart received data
+
+reg[7:0]                         tx_data;
+reg[7:0]                         tx_str;
+reg                              tx_data_valid;
+wire                             tx_data_ready;
+reg[7:0]                         tx_cnt;
+
+wire[7:0]                        rx_data;
+wire                             rx_data_valid;
+wire                             rx_data_ready;
+
+reg[31:0]                        wait_cnt;
+reg[3:0]                         state;
+
+wire rst_p = rst;
+
+assign rx_data_ready = 1'b1;    //always can receive data,
+
+always@(posedge clk or negedge rst_p)
+begin
+	if(rst_p == 1'b1)
+	begin
+		wait_cnt <= 32'd0;
+		tx_data <= 8'd0;
+		state <= IDLE;
+		tx_cnt <= 8'd0;
+		tx_data_valid <= 1'b0;
+	end
+	else
+	case(state)
+		IDLE:begin
+			state <= SEND;
+        end
+
+		SEND:begin
+			wait_cnt <= 32'd0;
+			tx_data <= tx_str;
+
+			if(tx_data_valid == 1'b1 && tx_data_ready == 1'b1 && tx_cnt < DATA_NUM - 1)//Send 12 bytes data
+			begin
+				tx_cnt <= tx_cnt + 8'd1; //Send data counter
+			end
+			else if(tx_data_valid && tx_data_ready)//last byte sent is complete
+			begin
+				tx_cnt <= 8'd0;
+				tx_data_valid <= 1'b0;
+				state <= WAIT;
+			end
+			else if(~tx_data_valid)
+			begin
+				tx_data_valid <= 1'b1;
+			end
+		end
+
+		WAIT:begin
+			wait_cnt <= wait_cnt + 32'd1;
+
+			if(rx_data_valid == 1'b1)
+			begin
+				tx_data_valid <= 1'b1;
+				tx_data <= rx_data;   // send uart received data
+			end
+			else if(tx_data_valid && tx_data_ready)
+			begin
+				tx_data_valid <= 1'b0;
+			end
+			else if(wait_cnt >= CLK_FRE * 1000_000) // wait for 1 second
+				state <= SEND;
+		end
+        
+		default:
+			state <= IDLE;
+	endcase
+end
+
+always@(*)
+	tx_str <= send_data[(DATA_NUM - 1 - tx_cnt) * 8 +: 8];
+
+uart_rx#
+(
+	.CLK_FRE(CLK_FRE),
+	.BAUD_RATE(UART_FRE)
+) uart_rx_inst
+(
+	.clk                        (clk),
+	.rst_p                      (rst_p),
+	.rx_data                    (rx_data),
+	.rx_data_valid              (rx_data_valid),
+	.rx_data_ready              (rx_data_ready),
+	.rx_pin                     (uart_rx)
+);
+
+uart_tx#
+(
+	.CLK_FRE(CLK_FRE),
+	.BAUD_RATE(UART_FRE)
+) uart_tx_inst
+(
+	.clk                        (clk),
+	.rst_p                      (rst_p),
+	.tx_data                    (tx_data),
+	.tx_data_valid              (tx_data_valid),
+	.tx_data_ready              (tx_data_ready),
+	.tx_pin                     (uart_tx)
+);
+endmodule

Semaine 1/UARTV2/uart_rx.v

@@ -0,0 +1,145 @@
+module uart_rx #(
+	parameter CLK_FREQ = 27_000_000,
+	parameter BAUD_RATE = 115200
+)(
+	input                        clk,               //clock input
+	input                        rst_p,             //asynchronous reset input, high active 
+	input                        rx_data_ready,     //data receiver module ready
+	input                        rx_pin,             //serial data input
+
+    output reg[7:0]              rx_data,           //received serial data
+	output reg                   rx_data_valid     //received serial data is valid
+);
+ 
+localparam                       CYCLE = CLK_FREQ * / BAUD_RATE;
+
+//state machine code
+localparam                       S_IDLE      = 1;
+localparam                       S_START     = 2;   //start bit
+localparam                       S_REC_BYTE  = 3;   //data bits
+localparam                       S_STOP      = 4;   //stop bit
+localparam                       S_DATA      = 5;
+
+reg[2:0]                         state;
+reg[2:0]                         next_state;
+
+reg                              rx_d0;             //delay 1 clock for rx_pin
+reg                              rx_d1;             //delay 1 clock for rx_d0
+wire                             rx_negedge;        //negedge of rx_pin
+reg[7:0]                         rx_bits;           //temporary storage of received data
+reg[15:0]                        cycle_cnt;         //baud counter
+reg[2:0]                         bit_cnt;           //bit counter
+
+assign rx_negedge = rx_d1 && ~rx_d0;    // Front déscendant
+
+always@(posedge clk or negedge rst_p)   // Filtrage du signial
+begin
+	if(rst_p == 1'b1)begin
+		rx_d0 <= 1'b0;
+		rx_d1 <= 1'b0;	
+        
+	end else begin
+		rx_d0 <= rx_pin;
+		rx_d1 <= rx_d0;
+	end
+end
+
+
+always@(posedge clk or negedge rst_p)begin  // Compteur d'etat
+	if(rst_p == 1'b1)
+		state <= S_IDLE;
+	else
+		state <= next_state;
+end
+
+always@(*)begin
+	case(state)
+		S_IDLE:
+			if(rx_negedge)                  // Detection du start bit
+				next_state = S_START;
+			else
+				next_state = S_IDLE;
+
+		S_START:
+			if(cycle_cnt == CYCLE - 1)      //one data cycle 
+				next_state = S_REC_BYTE;
+			else
+				next_state = S_START;
+
+		S_REC_BYTE:
+			if(cycle_cnt == CYCLE - 1  && bit_cnt == 3'd7)  //receive 8bit data
+				next_state = S_STOP;
+			else
+				next_state = S_REC_BYTE;
+
+		S_STOP:
+			if(cycle_cnt == CYCLE/2 - 1)    //half bit cycle,to avoid missing the next byte receiver
+				next_state = S_DATA;
+			else
+				next_state = S_STOP;
+
+		S_DATA:
+			if(rx_data_ready)               //data receive complete
+				next_state = S_IDLE;
+			else
+				next_state = S_DATA;
+
+		default:
+			next_state = S_IDLE;
+	endcase
+end
+
+always@(posedge clk or negedge rst_p)
+begin
+	if(rst_p == 1'b1)
+		rx_data_valid <= 1'b0;
+	else if(state == S_STOP && next_state != state)
+		rx_data_valid <= 1'b1;
+	else if(state == S_DATA && rx_data_ready)
+		rx_data_valid <= 1'b0;
+end
+
+always@(posedge clk or negedge rst_p)
+begin
+	if(rst_p == 1'b1)
+		rx_data <= 8'd0;
+	else if(state == S_STOP && next_state != state)
+		rx_data <= rx_bits;//latch received data
+end
+
+always@(posedge clk or negedge rst_p)
+begin
+	if(rst_p == 1'b1)
+		begin
+			bit_cnt <= 3'd0;
+		end
+	else if(state == S_REC_BYTE)
+		if(cycle_cnt == CYCLE - 1)
+			bit_cnt <= bit_cnt + 3'd1;
+		else
+			bit_cnt <= bit_cnt;
+	else
+		bit_cnt <= 3'd0;
+end
+
+
+always@(posedge clk or negedge rst_p)
+begin
+	if(rst_p == 1'b1)
+		cycle_cnt <= 16'd0;
+	else if((state == S_REC_BYTE && cycle_cnt == CYCLE - 1) || next_state != state)
+		cycle_cnt <= 16'd0;
+	else
+		cycle_cnt <= cycle_cnt + 16'd1;	
+end
+//receive serial data bit data
+always@(posedge clk or negedge rst_p)
+begin
+	if(rst_p == 1'b1)
+		rx_bits <= 8'd0;
+	else if(state == S_REC_BYTE && cycle_cnt == CYCLE/2 - 1)
+		rx_bits[bit_cnt] <= rx_pin;
+	else
+		rx_bits <= rx_bits; 
+end
+endmodule 

Semaine 1/UARTV2/uart_tx.v

@@ -0,0 +1,133 @@
+module uart_tx #(
+	parameter       CLK_FREQ = 27_000_000,
+	parameter       BAUD_RATE = 115200
+)(
+    input wire      clk,
+    input wire      rst_p,
+    input wire[7:0] data,
+    input wire      tx_data_valid,
+    
+    output wire     tx,
+    output reg      tx_data_ready
+);
+
+    localparam CYCLE = CLK_FREQ / BAUD_RATE; 
+
+    localparam IDLE  = 2'd0;
+    localparam START = 2'd1;
+    localparam DATA  = 2'd2;
+    localparam STOP  = 2'd3;
+
+    reg [1:0]   state = IDLE;
+    reg [1:0]   next_state;
+    reg [15:0]  cycle_cnt;      //baud counter
+    reg [3:0]   bit_index = 0;            
+    reg [15:0]  clk_count = 0;           
+    reg [7:0]   tx_data = 0;
+    reg         tx_reg;
+
+    assign tx = tx_reg;
+
+    always@(posedge clk or posedge rst_p)begin // Avance d'etat 
+        if(rst_p == 1'b1)
+            state <= IDLE;
+        else
+            state <= next_state;
+    end
+
+    always@(*) begin
+        case(state)
+            IDLE:
+                if(tx_data_valid == 1'b1)
+                    next_state = START;
+                else
+                    next_state = IDLE;
+
+            START:
+                if(cycle_cnt == CYCLE - 1)
+                    next_state = DATA;
+                else
+                    next_state = START;
+
+            DATA:
+                if(cycle_cnt == CYCLE - 1  && bit_cnt == 3'd7)
+                    next_state = STOP;
+                else
+                    next_state = DATA;
+
+            STOP:
+                if(cycle_cnt == CYCLE - 1)
+                    next_state = IDLE;
+                else
+                    next_state = STOP;
+            default:
+                next_state = IDLE;
+        endcase
+    end
+
+    always@(posedge clk or posedge rst_p)begin  // tx_data_ready block
+        if(rst_p == 1'b1)
+            begin
+                tx_data_ready <= 1'b0;
+            end
+
+        else if(state == IDLE)
+            if(tx_data_valid == 1'b1)
+                tx_data_ready <= 1'b0;
+            else
+                tx_data_ready <= 1'b1;
+
+        else if(state == STOP && cycle_cnt == CYCLE - 1)
+                tx_data_ready <= 1'b1;
+    end
+
+
+    always@(posedge clk or posedge rst_p) begin // tx_data_latch block
+        if(rst_p == 1'b1)begin
+                tx_data_latch <= 8'd0;
+
+        end else if(state == IDLE && tx_data_valid == 1'b1)
+                tx_data_latch <= tx_data;
+            
+    end
+
+    always@(posedge clk or posedge rst_p)begin  // DATA bit_cnt block
+        if(rst_p == 1'b1)begin
+                bit_cnt <= 3'd0;
+
+        end else if(state == DATA)
+            if(cycle_cnt == CYCLE - 1)
+                bit_cnt <= bit_cnt + 3'd1;
+            else
+                bit_cnt <= bit_cnt;
+        else
+            bit_cnt <= 3'd0;
+    end
+
+
+    always@(posedge clk or posedge rst_p)begin  // Cycle counter
+        if(rst_p == 1'b1)
+            cycle_cnt <= 16'd0;
+
+        else if((state == DATA && cycle_cnt == CYCLE - 1) || next_state != state)
+            cycle_cnt <= 16'd0;
+        else
+            cycle_cnt <= cycle_cnt + 16'd1;	
+    end
+
+    always@(posedge clk or posedge rst_p)begin  // tx state managment
+        if(rst_p == 1'b1)
+            tx_reg <= 1'b1;
+        else
+            case(state)
+                IDLE,STOP:
+                    tx_reg <= 1'b1; 
+                START:
+                    tx_reg <= 1'b0; 
+                DATA:
+                    tx_reg <= tx_data_latch[bit_cnt]; // SENDING BYTE HERE
+                default:
+                    tx_reg <= 1'b1; 
+            endcase
+    end
+endmodule