Added adc->dac path test

Now talking over the bus instead of using dpram

cores/primitive/lvds_comparator/lvds_comparator_spartan6.v

@@ -5,10 +5,10 @@ module lvds_comparator_spartan6_impl (
 );
     IBUFDS #(
         .DIFF_TERM("FALSE"),
-        .IOSTANDARD("LVDS33")
+        .IOSTANDARD("LVDS_33")
     ) lvds_buf (
         .O(o),
         .I(a),
         .IB(b)
     );
-endmodule
+endmodule

cores/system/mcu/rtl/mcu_peripherals.v

@@ -91,11 +91,10 @@ module mcu_peripherals (
     );
 
     wb_gpio_banks #(
-        .BASE_ADDR(GPIO_BASE_ADDR),
-        .NUM_BANKS(4)
+        .num_banks(4)
     ) gpio (
-        .i_wb_clk(i_clk),
-        .i_wb_rst(i_rst),
+        .i_clk(i_clk),
+        .i_rst(i_rst),
         .i_wb_dat(gpio_wbs_dat_w),
         .i_wb_adr(gpio_wbs_adr),
         .i_wb_we(gpio_wbs_we),

cores/system/mimas_sd_adc_r2r/mimas.ucf

@@ -0,0 +1,54 @@
+# Main clock input
+NET "aclk" LOC = P126;
+NET "aclk" TNM_NET = "SYS_CLK_PIN";
+TIMESPEC TS_SYS_CLK_PIN = PERIOD "SYS_CLK_PIN" 10 ns HIGH 50 %;
+
+# Boards button row
+NET "aresetn" LOC = P120;
+NET "aresetn" IOSTANDARD = LVCMOS33;
+NET "aresetn" PULLUP;
+
+NET "adc_a" LOC = P33;
+NET "adc_a" IOSTANDARD = LVDS_33;
+NET "adc_b" LOC = P32;
+NET "adc_b" IOSTANDARD = LVDS_33;
+NET "adc_o" LOC = P34;
+NET "adc_o" IOSTANDARD = LVCMOS33;
+
+NET "r2r[0]" LOC = P131;
+NET "r2r[1]" LOC = P133;
+NET "r2r[2]" LOC = P137;
+NET "r2r[3]" LOC = P139;
+NET "r2r[4]" LOC = P141;
+NET "r2r[5]" LOC = P1;
+NET "r2r[0]" IOSTANDARD = LVCMOS33;
+NET "r2r[1]" IOSTANDARD = LVCMOS33;
+NET "r2r[2]" IOSTANDARD = LVCMOS33;
+NET "r2r[3]" IOSTANDARD = LVCMOS33;
+NET "r2r[4]" IOSTANDARD = LVCMOS33;
+NET "r2r[5]" IOSTANDARD = LVCMOS33;
+
+NET "LED[0]" LOC = P119;
+NET "LED[0]" IOSTANDARD = LVCMOS33;
+NET "LED[0]" DRIVE = 8;
+NET "LED[1]" LOC = P118;
+NET "LED[1]" IOSTANDARD = LVCMOS33;
+NET "LED[1]" DRIVE = 8;
+NET "LED[2]" LOC = P117;
+NET "LED[2]" IOSTANDARD = LVCMOS33;
+NET "LED[2]" DRIVE = 8;
+NET "LED[3]" LOC = P116;
+NET "LED[3]" IOSTANDARD = LVCMOS33;
+NET "LED[3]" DRIVE = 8;
+NET "LED[4]" LOC = P115;
+NET "LED[4]" IOSTANDARD = LVCMOS33;
+NET "LED[4]" DRIVE = 8;
+NET "LED[5]" LOC = P114;
+NET "LED[5]" IOSTANDARD = LVCMOS33;
+NET "LED[5]" DRIVE = 8;
+NET "LED[6]" LOC = P112;
+NET "LED[6]" IOSTANDARD = LVCMOS33;
+NET "LED[6]" DRIVE = 8;
+NET "LED[7]" LOC = P111;
+NET "LED[7]" IOSTANDARD = LVCMOS33;
+NET "LED[7]" DRIVE = 8;

cores/system/mimas_sd_adc_r2r/mimas_sd_adc_r2r.core

@@ -0,0 +1,46 @@
+CAPI=2:
+
+name: joppeb:system:mimas_sd_adc_r2r:1.0
+description: Mimas top-level wiring sigma-delta ADC output directly to R2R DAC
+
+filesets:
+    rtl:
+        depend:
+            - joppeb:primitive:clkgen
+            - joppeb:signal:sd_adc_q15
+            - joppeb:util:conv
+        files:
+            - rtl/toplevel.v
+        file_type: verilogSource
+
+    mimas:
+        files:
+            - mimas.ucf : {file_type : UCF}
+            - options.tcl : {file_type : tclSource}
+
+targets:
+    default:
+        filesets:
+            - rtl
+        toplevel: toplevel
+
+    mimas:
+        filesets:
+            - rtl
+            - mimas
+        toplevel: toplevel
+        parameters:
+            - FPGA_SPARTAN6=true
+        default_tool: ise
+        tools:
+            ise:
+                family: Spartan6
+                device: xc6slx9
+                package: tqg144
+                speed: -2
+
+parameters:
+    FPGA_SPARTAN6:
+        datatype: bool
+        description: Select Spartan-6 family specific implementations
+        paramtype: vlogdefine

cores/system/mimas_sd_adc_r2r/options.tcl

@@ -0,0 +1,2 @@
+project set "Create Binary Configuration File" TRUE -process "Generate Programming File"
+project set "Keep Hierarchy" Yes -process "Synthesize - XST"

cores/system/mimas_sd_adc_r2r/rtl/toplevel.v

@@ -0,0 +1,91 @@
+`timescale 1ns/1ps
+
+module toplevel(
+    input wire aclk,
+    input wire aresetn,
+
+    input wire adc_a,
+    input wire adc_b,
+    output wire adc_o,
+
+    output wire [5:0] r2r,
+    output wire [7:0] LED
+);
+    `include "conv.vh"
+
+    // Clocking
+    wire clk_100;
+    assign clk_100 = aclk;
+    wire clk_15;
+    clkgen #(
+        .CLK_IN_HZ(100000000),
+        .CLKFX_DIVIDE(20),
+        .CLKFX_MULTIPLY(3)
+    ) clk_gen_15 (
+        .clk_in(clk_100),
+        .clk_out(clk_15)
+    );
+
+    // Asynchronous assert on reset button, synchronous release in clk_15 domain.
+    localparam [17:0] RESET_RELEASE_CYCLES = 18'd150000; // ~10 ms @ 15 MHz
+    reg [17:0] rst_cnt = 18'd0;
+    reg        sys_reset_r = 1'b1;
+    always @(posedge clk_15 or negedge aresetn) begin
+        if (!aresetn) begin
+            rst_cnt <= 18'd0;
+            sys_reset_r <= 1'b1;
+        end else if (sys_reset_r) begin
+            if (rst_cnt == RESET_RELEASE_CYCLES - 1'b1)
+                sys_reset_r <= 1'b0;
+            else
+                rst_cnt <= rst_cnt + 1'b1;
+        end
+    end
+
+    wire signed [15:0] signal_q15;
+    wire signal_valid;
+    sd_adc_q15 #(
+        .R_OHM(3300),
+        .C_PF(220)
+    ) sd_adc (
+        .i_clk_15(clk_15),
+        .i_rst_n(!sys_reset_r),
+        .i_adc_a(adc_a),
+        .i_adc_b(adc_b),
+        .o_adc(adc_o),
+        .o_signal_q15(signal_q15),
+        .o_signal_valid(signal_valid)
+    );
+
+    // signal_q15 is unipolar and biased (0-3.3V -> 0..32767)
+    reg signed [15:0] signal_unbiased_q15 = 16'sd0;
+    reg signal_unbiased_valid = 1'b0;
+    localparam bias = 2**14;
+    localparam gain = 2;
+    always @(posedge clk_15) begin
+        if (sys_reset_r) begin
+            signal_unbiased_q15 <= 16'sd0;
+            signal_unbiased_valid <= 1'b0;
+        end else begin
+            signal_unbiased_valid <= signal_valid;
+            if (signal_valid) begin
+                signal_unbiased_q15 <= (signal_q15 - $signed(bias)) * gain;
+            end
+        end
+    end
+
+    reg [5:0] dac_code = 6'd0;
+    always @(posedge clk_15) begin
+        if (sys_reset_r)
+            dac_code <= 6'd0;
+        else if (signal_unbiased_valid)
+            dac_code <= q15_to_uq16(signal_unbiased_q15) >> 10;
+    end
+
+    assign r2r = dac_code;
+
+    // Quick status indication: show ADC validity and most recent DAC code.
+    assign LED[0] = signal_valid;
+    assign LED[6:1] = dac_code;
+    assign LED[7] = sys_reset_r;
+endmodule

cores/system/test/sw/sweep/sweep.c

@@ -35,13 +35,13 @@ void main(){
     irq_init();
 
     *LEDGR = 1;
-    *TIMER_LD = 2 * 15000000/1000;
+    *TIMER_LD = 1000 * 15000;
 
     for(;;){
-        for(int i=1000; i<10000; i+=10){
+        for(int i=500; i<6000; i+=10){
             *R_FREQ = i;
             *LEDS = i>>4;
-            // for(int j=0; j<80; j++) asm volatile("nop");
+            for(int j=0; j<800; j++) asm volatile("nop");
         }
     }
 }

cores/wb/wb_gpio_banks/rtl/wb_gpio_banks.v

@@ -13,7 +13,7 @@ module wb_gpio_banks #(
     input  wire         i_wb_we,
     input  wire         i_wb_cyc,
     input  wire         i_wb_stb,
-    output wire         o_wb_ack,
+    output reg          o_wb_ack,
 
 	input wire [num_banks*32-1:0] i_gpio,
 	output wire [num_banks*32-1:0] o_gpio
@@ -48,8 +48,8 @@ module wb_gpio_banks #(
 
 	integer bi;
 	always @* begin
-		o_wb_rdt = 0;
-		o_wb_ack = 0;
+		o_wb_rdt = 32'h00000000;
+		o_wb_ack = 1'b0;
 		for(bi=0; bi<num_banks; bi=bi+1) begin
 			if(bank_sel[bi]) begin
 				o_wb_rdt = bank_rdt[bi*32 +: 32];