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Enhance DHT11 interface: add start signal and busy output, improve FSM for better data handling

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Gamenight77
2025-05-14 10:27:46 +02:00
parent 1d6677d67d
commit 2a153aa1eb
1 changed files with 191 additions and 16 deletions
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207
Semaine_5/DHT11/src/verilog/dht11_interface.v
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@@ -1,35 +1,210 @@
module dht11_interface (
input wire i_clk, // 27 MHz
inout wire io_dht11_sig,
input wire i_start,
output wire o_dht11_data_ready,
output wire o_busy,
output wire [7:0] o_temp_data,
output wire [7:0] o_hum_data,
output wire o_dht11_error
);
// === DHT11 INTERFACE ===
// Le module DHT11 est connecté à la broche io_dht11_sig.
// La communication se fait en mode bidirectionnel.
wire sig_dir;
wire sig_out;
// === PARAMÈTRES ===
parameter CLK_FREQ = 27_000_000;
localparam T_18MS = CLK_FREQ * 18 / 1000; // cycles pour 18ms
localparam T_80US = CLK_FREQ * 81 / 1_000_000;
localparam T_79US = CLK_FREQ * 79 / 1_000_000;
localparam T_71US = CLK_FREQ * 71 / 1_000_000;
localparam T_51US = CLK_FREQ * 51 / 1_000_000;
localparam T_50US = CLK_FREQ * 50 / 1_000_000;
localparam T_49US = CLK_FREQ * 49 / 1_000_000;
localparam T_40US = CLK_FREQ * 40 / 1_000_000;
localparam T_28US = CLK_FREQ * 28 / 1_000_000;
localparam T_20US = CLK_FREQ * 20 / 1_000_000;
assign io_dht11_sig = sig_dir ? sig_out : 1'bz;
// === Signal bidirectionnel ===
reg sig_dir;
reg sig_out;
wire sig_in;
assign io_dht11_sig = sig_dir ? sig_out : 1'bz; // Si sig_dir = 1, on force la valeur de sig_out sur la ligne, sinon on laisse la ligne libre (1'bz)
assign sig_in = io_dht11_sig;
// === REGISTRES ===
reg [3:0] state;
reg [31:0] timer;
reg [7:0] temp_data, hum_data;
reg [7:0] temp_dec, hum_dec, checksum;
reg [2:0] bit_count;
reg [5:0] bit_index;
reg [39:0] raw_data;
// === INITIALISATION ===
initial begin
sig_dir = 0;
sig_out = 1;
timer = 0;
state = IDLE;
bit_index = 0;
raw_data = 0;
o_dht11_data_ready = 0;
o_dht11_error = 0;
end
// === FSM ===
localparam IDLE = 3'd0, // Pull up la ligne
localparam IDLE = 4'd0, // Pull up la ligne
START = 4'd1, // Pull low 18ms
WAIT_RESPONSE = 4'd2, // Release la ligne (entre 20 et 40us)
RESPONSE_LOW = 4'd3, // DHT11 pull low 80us
RESPONSE_HIGH = 4'd4, // DHT11 pull high 80us
READ_READ_BITS_LOW = 4'd5,
READ_READ_BITS_HIGH = 4'd6,
DONE = 4'd7,
ERROR = 4'd8;
START = 3'd1, // Pull low 18ms
WAIT_RESPONSE = 3'd2, // Release la ligne (entre 20 et 40us)
READ_HUM_INT = 3'd3,
READ_HUM_DEC = 3'd4;
READ_TEMP_INT = 3'd5,
READ_TEMP_DEC = 3'd6,
READ_CHECKSUM = 3'd7, // Last 8 bits of {1st Byte + 2nd Byte + 3rd Byte+ 4th Byte}
DONE = 3'd8;
// === FSM principale ===
always @(posedge i_clk) begin
case (state)
IDLE: begin
sig_dir <= 0;
sig_out <= 1;
timer <= 0;
bit_index <= 0;
raw_data <= 0;
o_busy <= 0;
if (i_start) begin
sig_dir <= 1;
sig_out <= 0;
timer <= 0;
o_busy <= 1;
state <= START;
o_dht11_data_ready <= 0;
o_dht11_error <= 0;
end
end
START: begin
timer <= timer + 1;
if (timer >= T_18MS) begin
sig_dir <= 0; // libérer la ligne
timer <= 0;
state <= WAIT_RESPONSE;
end
end
WAIT_RESPONSE: begin
timer <= timer + 1;
if (sig_in == 0) begin
if (timer > T_20US && timer < T_40US) begin
timer <= 0;
state <= RESPONSE_LOW;
end else begin
state <= ERROR;
end
end else if (timer > T_40US) begin
state <= ERROR;
end
end
RESPONSE_LOW: begin
timer <= timer + 1;
if (sig_in == 1) begin
if (timer > T_79US && timer < T_80US) begin
timer <= 0;
state <= RESPONSE_HIGH;
end else begin
state <= ERROR;
end
end else if (timer > T_80US) begin
state <= ERROR;
end
end
RESPONSE_HIGH: begin
timer <= timer + 1;
if (sig_in == 0) begin
if (timer > T_79US && timer < T_80US) begin
timer <= 0;
state <= READ_BITS_LOW;
end else begin
state <= ERROR;
end
end else if (timer > T_80US) begin
state <= ERROR;
end
end
READ_BITS_LOW: begin
timer <= timer + 1;
if (sig_in == 1) begin
if (timer > T_49US && timer < T_51US) begin
timer <= 0;
state <= READ_BITS_HIGH;
end else begin
state <= ERROR;
end
end else if (timer > T_28US) begin
state <= ERROR;
end
end
READ_BITS_HIGH: begin // entre 26 et 28us = 0 et ~70us = 1
timer <= timer + 1;
if (sig_in == 0) begin
if (timer < T_26US) begin
state <= ERROR;
end
raw_data <= {raw_data[38:0], (timer > T_28US)}; // 1 si high > ~28us
timer <= 0;
bit_index <= bit_index + 1;
if (bit_index == 39) begin
state <= DONE;
end else begin
state <= READ_BITS_LOW;
end
end else if (timer > T_71US) begin
state <= ERROR;
end
end
DONE: begin
hum_data <= raw_data[39:32];
hum_dec <= raw_data[31:24];
temp_data <= raw_data[23:16];
temp_dec <= raw_data[15:8];
checksum <= raw_data[7:0];
if (checksum == (raw_data[39:32] + raw_data[31:24] + raw_data[23:16] + raw_data[15:8])) begin
o_hum_data <= raw_data[39:32];
o_temp_data <= raw_data[23:16];
o_dht11_data_ready <= 1;
end else begin
o_dht11_error <= 1;
end
o_busy <= 0;
state <= IDLE;
end
ERROR: begin
o_dht11_error <= 1;
state <= IDLE;
end
endcase
end
endmodule