add reset pin

spi_master.v

@@ -30,6 +30,7 @@ spi_master
 )
 (
 	input clk,
+	input rst_L,
 `ifndef SPI_MASTER_NO_READ
 	output reg [WID-1:0] from_slave,
 	input miso,
@@ -138,7 +139,18 @@ endtask
 initial ready_to_arm = 1;
 
 always @ (posedge clk) begin
-	case (state)
+	if (!rst_L) begin
+		idle_state();
+		finished <= 0;
+		state <= WAIT_ON_ARM;
+		ready_to_arm <= 1;
+`ifndef SPI_MASTER_NO_READ
+		from_slave <= 0;
+`endif
+`ifndef SPI_MASTER_NO_WRITE
+		send_buf <= 0;
+`endif
+	end else case (state)
 	WAIT_ON_ARM: begin
 `ifdef SIMULATION
 		if (!ready_to_arm)

spi_master_ss_template.v

@@ -17,6 +17,7 @@ module `SPI_MASTER_SS_NAME
 )
 (
 	input clk,
+	input rst_L,
 `ifndef SPI_MASTER_NO_READ
 	output [WID-1:0] from_slave,
 	input miso,
@@ -45,6 +46,7 @@ assign ss_L = !ss;
 	.PHASE(PHASE)
 ) master (
 	.clk(clk),
+	.rst_L(rst_L),
 `ifndef SPI_MASTER_NO_READ
 	.from_slave(from_slave),
 	.miso(miso),
@@ -72,7 +74,12 @@ task master_arm();
 endtask
 
 always @ (posedge clk) begin
-	case (state)
+	if (!rst_L) begin
+		state <= WAIT_ON_ARM;
+		timer <= 0;
+		arm_master <= 0;
+		ss <= 0;
+	end else case (state)
 	WAIT_ON_ARM: begin
 		if (arm) begin
 			timer <= 1;

spi_slave.v

@@ -20,6 +20,7 @@ spi_slave
 )
 (
 	input clk,
+	input rst_L,
 	input sck,
 	input ss_L,
 `ifndef SPI_SLAVE_NO_READ
@@ -96,53 +97,69 @@ task check_counter();
 endtask
 
 always @ (posedge clk) begin
-	sck_delay <= sck;
+	if (!rst_L) begin
-	ss_delay <= ss;
+		sck_delay <= 0;
-
-	case ({ss_delay, ss})
-	2'b01: begin // rising edge of SS
 		bit_counter <= 0;
+		ss_delay <= 0;
+		ready_at_start <= 0;
+`ifndef SPI_SLAVE_NO_READ
+		from_master <= 0;
+`endif
+`ifndef SPI_SLAVE_NO_WRITE
+		miso <= 0;
+		send_buf <= 0;
+`endif
 		finished <= 0;
 		err <= 0;
-		ready_at_start <= rdy;
+	end else begin
+		sck_delay <= sck;
+		ss_delay <= ss;
 
-		setup_bits();
+		case ({ss_delay, ss})
-	end
+		2'b01: begin // rising edge of SS
-	2'b10: begin // falling edge
+			bit_counter <= 0;
-		finished <= ready_at_start;
+			finished <= 0;
-	end
+			err <= 0;
-	2'b11: begin
+			ready_at_start <= rdy;
-		case ({sck_delay, sck})
-		2'b01: begin // rising edge
-			if (PHASE == 1) begin
-				write_data();
-			end else begin
-				read_data();
-			end
 
-			if (POLARITY == 0) begin
+			setup_bits();
-				check_counter();
-			end
 		end
 		2'b10: begin // falling edge
-			if (PHASE == 1) begin
+			finished <= ready_at_start;
-				read_data();
+		end
-			end else begin
+		2'b11: begin
-				write_data();
+			case ({sck_delay, sck})
-			end
+			2'b01: begin // rising edge
-
+				if (PHASE == 1) begin
-			if (POLARITY == 1) begin
+					write_data();
-				check_counter();
+				end else begin
-			end
+					read_data();
+				end
+
+				if (POLARITY == 0) begin
+					check_counter();
+				end
+			end
+			2'b10: begin // falling edge
+				if (PHASE == 1) begin
+					read_data();
+				end else begin
+					write_data();
+				end
+
+				if (POLARITY == 1) begin
+					check_counter();
+				end
+			end
+			default: ;
+			endcase
+		end
+		2'b00: if (!rdy) begin
+			finished <= 0;
+			err <= 0;
 		end
-		default: ;
 		endcase
 	end
-	2'b00: if (!rdy) begin
-		finished <= 0;
-		err <= 0;
-	end
-	endcase
 end
 
 endmodule

tests/simtop.v

@@ -12,6 +12,7 @@ module simtop
 	parameter WID_LEN = 5
 ) (
 	input clk,
+	input rst_L,
 `ifndef SPI_MASTER_NO_WRITE
 	input [WID-1:0] master_to_slave,
 	output [WID-1:0] from_master,
@@ -62,6 +63,7 @@ reg slave_error;
 	.WID_LEN(WID_LEN)
 ) master (
 	.clk(clk),
+	.rst_L(rst_L),
 `ifndef SPI_MASTER_NO_WRITE
 	.to_slave(master_to_slave),
 	.mosi(mosi),
@@ -86,6 +88,7 @@ reg slave_error;
 	.WID_LEN(WID_LEN)
 ) slave (
 	.clk(clk),
+	.rst_L(rst_L),
 	.sck(sck),
 	.ss_L(ss_L),
 `ifndef SPI_MASTER_NO_WRITE

tests/write_read.cpp

@@ -31,6 +31,17 @@ static void progress_n(int f) {
 		progress();
 }
 
+static void test_reset_pin(void) {
+	sim->rst_L = 0;
+	progress();
+	sim->rdy = 1;
+	sim->activate = 1;
+
+	progress_n(200);
+	assert(!sim->master_finished);
+	sim->rst_L = 1;
+}
+
 static void test_cross_transfer(unsigned m2s, unsigned s2m) {
 #ifndef SPI_MASTER_NO_WRITE
 	sim->master_to_slave = m2s;
@@ -39,6 +50,7 @@ static void test_cross_transfer(unsigned m2s, unsigned s2m) {
 	sim->slave_to_master = s2m;
 #endif
 
+	sim->rst_L = 1;
 	progress();
 	SET_SS(sim, 1);
 	sim->rdy = 1;
@@ -74,6 +86,19 @@ static void test_cross_transfer(unsigned m2s, unsigned s2m) {
 #endif
 }
 
+static void test_interrupted(unsigned m2s, unsigned s2m) {
+	sim->rst_L = 1;
+	progress();
+
+	sim->rdy = 1;
+	sim->activate = 1;
+	progress_n(6);
+	sim->rst_L = 0;
+	progress_n(100);
+	sim->rst_L = 1;
+	test_cross_transfer(m2s, s2m);
+}
+
 int main(int argc, char **argv) {
 	Verilated::commandArgs(argc, argv);
 	Verilated::traceEverOn(true);
@@ -84,13 +109,21 @@ int main(int argc, char **argv) {
 	sim->activate = 0;
 	sim->rdy = 0;
 
+	test_reset_pin();
 	test_cross_transfer(0b101010101010101010101010, 0b010101010101010101010101);
 	test_cross_transfer(0b110011001100110011001100, 0b001100110011001100110011);
+	test_reset_pin();
 
 	for (int i = 0; i < 10000; i++) {
 		unsigned m2s = rand() & ((1 << WID) - 1);
 		unsigned s2m = rand() & ((1 << WID) - 1);
-		test_cross_transfer(m2s, s2m);
+		if (i % (((rand() + 1) % 32) + 1) == 0)
+			test_interrupted(m2s, s2m);
+		else
+			test_cross_transfer(m2s, s2m);
+		if (i % (((rand() + 1) % 64) + 1) == 0)
+			test_reset_pin();
+
 	}
 
 	sim->final();