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forked from tanchou/Verilog

uart_rx valid

This commit is contained in:
Gamenight77
2025-05-05 09:51:23 +02:00
parent c9a5fba97e
commit fc48941459
7 changed files with 353 additions and 4 deletions

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@@ -1,4 +1,4 @@
module uart_rx
module other_uart_rx
#(
parameter CLK_FRE = 27, //clock frequency(Mhz)
parameter BAUD_RATE = 115200 //serial baud rate

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@@ -0,0 +1,133 @@
module other_uart_tx
#(
parameter CLK_FRE = 27, //clock frequency(Mhz)
parameter BAUD_RATE = 115200 //serial baud rate
)
(
input clk, //clock input
input rst_n, //asynchronous reset input, low active
input[7:0] tx_data, //data to send
input tx_data_valid, //data to be sent is valid
output reg tx_data_ready, //send ready
output tx_pin //serial data output
);
//calculates the clock cycle for baud rate
localparam CYCLE = CLK_FRE * 1000000 / BAUD_RATE;
//state machine code
localparam S_IDLE = 1;
localparam S_START = 2;//start bit
localparam S_SEND_BYTE = 3;//data bits
localparam S_STOP = 4;//stop bit
reg[2:0] state;
reg[2:0] next_state;
reg[15:0] cycle_cnt; //baud counter
reg[2:0] bit_cnt;//bit counter
reg[7:0] tx_data_latch; //latch data to send
reg tx_reg; //serial data output
assign tx_pin = tx_reg;
always@(posedge clk or negedge rst_n)
begin
if(rst_n == 1'b0)
state <= S_IDLE;
else
state <= next_state;
end
always@(*)
begin
case(state)
S_IDLE:
if(tx_data_valid == 1'b1)
next_state <= S_START;
else
next_state <= S_IDLE;
S_START:
if(cycle_cnt == CYCLE - 1)
next_state <= S_SEND_BYTE;
else
next_state <= S_START;
S_SEND_BYTE:
if(cycle_cnt == CYCLE - 1 && bit_cnt == 3'd7)
next_state <= S_STOP;
else
next_state <= S_SEND_BYTE;
S_STOP:
if(cycle_cnt == CYCLE - 1)
next_state <= S_IDLE;
else
next_state <= S_STOP;
default:
next_state <= S_IDLE;
endcase
end
always@(posedge clk or negedge rst_n)
begin
if(rst_n == 1'b0)
begin
tx_data_ready <= 1'b0;
end
else if(state == S_IDLE)
if(tx_data_valid == 1'b1)
tx_data_ready <= 1'b0;
else
tx_data_ready <= 1'b1;
else if(state == S_STOP && cycle_cnt == CYCLE - 1)
tx_data_ready <= 1'b1;
end
always@(posedge clk or negedge rst_n)
begin
if(rst_n == 1'b0)
begin
tx_data_latch <= 8'd0;
end
else if(state == S_IDLE && tx_data_valid == 1'b1)
tx_data_latch <= tx_data;
end
always@(posedge clk or negedge rst_n)
begin
if(rst_n == 1'b0)
begin
bit_cnt <= 3'd0;
end
else if(state == S_SEND_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_n)
begin
if(rst_n == 1'b0)
cycle_cnt <= 16'd0;
else if((state == S_SEND_BYTE && cycle_cnt == CYCLE - 1) || next_state != state)
cycle_cnt <= 16'd0;
else
cycle_cnt <= cycle_cnt + 16'd1;
end
always@(posedge clk or negedge rst_n)
begin
if(rst_n == 1'b0)
tx_reg <= 1'b1;
else
case(state)
S_IDLE,S_STOP:
tx_reg <= 1'b1;
S_START:
tx_reg <= 1'b0;
S_SEND_BYTE:
tx_reg <= tx_data_latch[bit_cnt];
default:
tx_reg <= 1'b1;
endcase
end
endmodule

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@@ -1,3 +1,3 @@
@echo off
echo === Lancement de GTKWave ===
gtkwave runs/uart_loopback.vcd
gtkwave runs/uart_rx.vcd

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@@ -6,7 +6,7 @@ setlocal enabledelayedexpansion
set OUT=runs/sim.vvp
:: Top-level testbench module
set TOP=tb_uart_tx
set TOP=tb_uart_rx
:: Répertoires contenant des fichiers .v
set DIRS=src/verilog tests/verilog IP/verilog

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@@ -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_enable, //data receiver module ready
input rx_pin, //serial data input
output reg[7:0] rx_data, //received serial data
output reg rx_received //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 posedge 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 posedge 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_enable) //data receive complete
next_state = S_IDLE;
else
next_state = S_DATA;
default:
next_state = S_IDLE;
endcase
end
always@(posedge clk or posedge rst_p)
begin
if(rst_p == 1'b1)
rx_received <= 1'b0;
else if(state == S_STOP && next_state != state)
rx_received <= 1'b1;
else if(state == S_DATA && rx_enable)
rx_received <= 1'b0;
end
always@(posedge clk or posedge 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 posedge 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 posedge 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 posedge 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

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@@ -0,0 +1,67 @@
`timescale 1ns / 1ps
module tb_uart_rx;
reg clk = 0;
reg rx;
reg [7:0] data_in;
reg [7:0] data_out;
reg tx_data_valid;
reg tx_data_ready;
reg rx_received;
wire rx_enable = 1'b1; // Enable the receiver
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;
other_uart_tx tx_instance (
.clk(clk),
.tx_pin(rx),
.tx_data(data_in),
.tx_data_valid(tx_data_valid),
.tx_data_ready(tx_data_ready),
.rst_n(1'b1)
);
uart_rx #(
.CLK_FREQ(CLK_FREQ),
.BAUD_RATE(BAUD_RATE)
) rx_instance (
.clk(clk),
.rx_pin(rx),
.rx_data(data_out),
.rx_received(rx_received),
.rx_enable(rx_enable)
);
always #(CLK_PERIOD_NS/2) clk = ~clk;
initial begin
$dumpfile("runs/uart_rx.vcd");
$dumpvars(0, tb_uart_rx);
$display("======== Start UART RX test =========");
#100;
data_in = 8'd123; // Data to send
wait(tx_data_ready); // Wait for the transmitter to be ready
#1; // Small delay to ensure the data is latched
tx_data_valid = 1'b1; // Indicate that the data is valid
wait(tx_data_ready == 0);
tx_data_valid = 1'b0; // Clear the valid signal
wait(rx_received); // Wait for the receiver to receive the data
$display("Data sent: %d", data_in);
$display("Data received: %d", data_out); // Display the received data
$display("======== END UART RX test =========");
$finish;
end
endmodule

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@@ -13,7 +13,7 @@ module tb_uart_tx;
always #18.5 clk = ~clk;
uart_rx rx_instance(
other_uart_rx rx_instance(
.clk(clk),
.rx_pin(tx), // tx is connected to rx for testing
.rst_n(1'b1),
@@ -38,6 +38,8 @@ module tb_uart_tx;
$dumpfile("runs/uart_tx.vcd");
$dumpvars(0, tb_uart_tx);
$display("======== Start UART TX test =========");
#100;
data_in <= 8'd234; // 234
@@ -66,6 +68,8 @@ module tb_uart_tx;
$display("Data received: %d", data_out); // Afficher la valeur recu
$display("Data expected: %d", data_in); // Afficher la valeur envoyee
$display("======== END UART TX test =========");
#1000;
$stop;
end