XC2CModel: Continued initial macrocell implementation

azonenberg · azonenberg · commit 546ceb64a3f2 · 2017-06-24T23:52:03.000-07:00
diff --git a/hdl/xc2c-model/XC2CDevice.v b/hdl/xc2c-model/XC2CDevice.v
@@ -174,6 +174,8 @@ module XC2CDevice(
 	////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 	// The JTAG TAP (for now, basic bitstream config only)
 
+	wire			config_done_rst;
+
 	XC2CJTAG #(
 		.MACROCELLS(MACROCELLS),
 		.PACKAGE(PACKAGE),
@@ -195,14 +197,15 @@ module XC2CDevice(
 		.config_write_addr(config_write_addr),
 		.config_write_data(config_write_data),
 
-		.config_done(done)
+		.config_done(done),
+		.config_done_rst(config_done_rst)
 	);
 
 	////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 	// Global routing
 
-	//TODO: input buffers and muxes for these based on InZ etc
-	wire[31:0]		macrocell_to_zia = 32'h0;
+	//TODO: muxes for iob_in
+	wire[31:0]		macrocell_to_zia;
 	wire[31:0]		ibuf_to_zia = iob_in;
 
 	//Left side (FB2)
@@ -272,8 +275,8 @@ module XC2CDevice(
 	////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 	// Macrocells
 
-	wire[15:0]		left_mc_out;
-	wire[15:0]		right_mc_out;
+	wire[15:0]		left_mc_to_obuf;
+	wire[15:0]		right_mc_to_obuf;
 
 	genvar g;
 	generate
@@ -285,7 +288,9 @@ module XC2CDevice(
 				.pterm_b(left_pterms[g*3 + 9]),
 				.pterm_c(left_pterms[g*3 + 10]),
 				.or_term(left_orterms[g]),
-				.mc_out(left_mc_out[g])
+				.config_done_rst(config_done_rst),
+				.mc_to_zia(macrocell_to_zia[g + 16]),
+				.mc_to_obuf(left_mc_to_obuf[g])
 			);
 
 			XC2CMacrocell right(
@@ -294,7 +299,9 @@ module XC2CDevice(
 				.pterm_b(right_pterms[g*3 + 9]),
 				.pterm_c(right_pterms[g*3 + 10]),
 				.or_term(right_orterms[g]),
-				.mc_out(right_mc_out[g])
+				.config_done_rst(config_done_rst),
+				.mc_to_zia(macrocell_to_zia[g]),
+				.mc_to_obuf(right_mc_to_obuf[g])
 			);
 
 		end
@@ -311,18 +318,14 @@ module XC2CDevice(
 	//Drive all unused outputs to 0, then hook up our outputs
 	//Should be X, !X, X, X
 	assign iob_out[31:7] = 25'h0;
-	assign iob_out[6] = right_mc_out[6];
-	assign iob_out[5] = right_mc_out[5];
-	assign iob_out[4] = right_mc_out[4];
-	assign iob_out[3] = right_mc_out[3];
-
-	//assign iob_out[5] = right_pterms[22];		//pterm, should be copy of x
-	//assign iob_out[4] = right_mc_out[3];		//led_0, constant 1: OR arrays 0 xor 1
-	//assign iob_out[3] = right_mc_out[4];		//led_1, passthrough of pterm C
-												//for MC4 this is pterm 22
+	assign iob_out[6] = right_mc_to_obuf[6];
+	assign iob_out[5] = right_mc_to_obuf[5];
+	assign iob_out[4] = right_mc_to_obuf[4];
+	assign iob_out[3] = right_mc_to_obuf[3];
+
 	assign iob_out[2:0] = 3'h0;
 
 	//Helper to keep stuff from getting optimized out
-	assign dbgout = ^right_mc_out ^ ^left_mc_out;
+	assign dbgout = ^macrocell_to_zia ^ ^right_mc_to_obuf ^ ^left_mc_to_obuf;
 
 endmodule
diff --git a/hdl/xc2c-model/XC2CJTAG.v b/hdl/xc2c-model/XC2CJTAG.v
@@ -25,7 +25,7 @@ module XC2CJTAG(
 	config_erase,
 	config_read_en, config_read_addr, config_read_data,
 	config_write_en, config_write_addr, config_write_data,
-	config_done);
+	config_done, config_done_rst);
 
 	////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 	// Device configuration
@@ -59,6 +59,7 @@ module XC2CJTAG(
 	output reg[SHREG_WIDTH-1:0]	config_write_data	= 0;
 
 	output wire					config_done;
+	output reg					config_done_rst		= 0;
 
 	////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 	// The core JTAG state machine
@@ -242,6 +243,7 @@ module XC2CJTAG(
 	always @(posedge tck) begin
 
 		config_erase			<= 0;
+		config_done_rst			<= 0;
 
 		case(state)
 
@@ -286,6 +288,7 @@ module XC2CJTAG(
 				//TODO: check DONE / transfer bits first
 				if(ir_shreg == INST_ISC_PROGRAM) begin
 					configured		<= 1;
+					config_done_rst <= 1;
 				end
 
 				//TODO: copy EEPROM to RAM when we get an ISC_INIT command
diff --git a/hdl/xc2c-model/XC2CMacrocell.v b/hdl/xc2c-model/XC2CMacrocell.v
@@ -20,7 +20,8 @@ module XC2CMacrocell(
 	config_bits,
 	pterm_a, pterm_b, pterm_c,
 	or_term,
-	mc_out
+	mc_to_zia, mc_to_obuf,
+	config_done_rst
 	);
 
 	////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -33,8 +34,10 @@ module XC2CMacrocell(
 	input wire					pterm_c;
 
 	input wire					or_term;
+	input wire					config_done_rst;
 
-	output reg					mc_out;
+	output reg					mc_to_zia;
+	output reg					mc_to_obuf;
 
 	////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 	// Macrocell XOR
@@ -51,11 +54,44 @@ module XC2CMacrocell(
 		endcase
 	end
 
+	////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+	// Macrocell flipflop
+
+	reg							mc_dff = 1;
+
+	//Flipflop reset
+	always @(/*posedge config_done_rst*/*) begin
+		mc_dff					<= !config_bits[0];
+	end
+
 	////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 	// Final output muxing
 
+	//TODO: mux for bit 15 (ibuf/mc flipflop)
+
 	always @(*) begin
-		mc_out					<= xor_out;
+
+		//Enable for macrocell->ZIA driver (active low so we're powered down when device is blank)
+		if(!config_bits[12]) begin
+
+			//See where macrocell->ZIA driver should go
+			if(config_bits[13])
+				mc_to_zia				<= mc_dff;
+			else
+				mc_to_zia				<= xor_out;
+
+		end
+
+		//Output driver powered down, feed a constant zero into the ZIA to prevent spurious toggles
+		else
+			mc_to_zia					<= 1'b0;
+
+		//Mux for pad driver
+		if(config_bits[7])
+			mc_to_obuf					<= xor_out;
+		else
+			mc_to_obuf					<= mc_dff;
+
 	end
 
 endmodule
