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Added sampler and RC model

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This commit is contained in:
Jojojoppe
2025-10-01 21:15:20 +02:00
parent ee58fccba4
commit e0151d093f
17 changed files with 319 additions and 13 deletions
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10
CON/io.cst
View File

@@ -4,13 +4,17 @@
//Tool Version: V1.9.12
//Part Number: GW1NSR-LV4CQN48PC7/I6
//Device: GW1NSR-4C
//Created Time: Wed 10 01 13:41:57 2025
//Created Time: Wed 10 01 18:02:30 2025
IO_LOC "adc1_A" 39,40;
IO_PORT "adc1_A" IO_TYPE=LVDS25 PULL_MODE=NONE BANK_VCCIO=3.3;
IO_LOC "adc1_O" 41;
IO_PORT "adc1_O" IO_TYPE=LVCMOS33 PULL_MODE=NONE DRIVE=8 BANK_VCCIO=3.3;
IO_LOC "led" 10;
IO_PORT "led" IO_TYPE=LVCMOS33 PULL_MODE=NONE DRIVE=8 BANK_VCCIO=3.3;
IO_LOC "button" 14;
IO_PORT "button" IO_TYPE=LVCMOS18 PULL_MODE=UP BANK_VCCIO=1.8;
IO_LOC "reset_n" 15;
IO_PORT "reset_n" IO_TYPE=LVCMOS18 PULL_MODE=UP BANK_VCCIO=1.8;
IO_LOC "clk" 45;
IO_PORT "clk" IO_TYPE=LVCMOS33 PULL_MODE=UP BANK_VCCIO=3.3;
IO_LOC "button" 14;
IO_PORT "button" IO_TYPE=LVCMOS18 PULL_MODE=UP BANK_VCCIO=1.8;

1
CON/timing.sdc
View File

@@ -5,3 +5,4 @@
//Created Time: 2025-10-01 16:50:37
create_clock -name CLK_IN -period 37.037 -waveform {0 18.518} [get_ports {clk}]
create_clock -name CLK_120 -period 8.333 -waveform {0 4.167} [get_nets {clk_120}]
create_clock -name CLK_15 -period 66.666 -waveform {0 33.333} [get_nets {clk_15}]

43
HW/sampling.v Normal file
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@@ -0,0 +1,43 @@
`timescale 1ns/1ps
module sampling(
input wire adc_A,
input wire adc_B,
output wire adc_O,
input wire clk,
input wire reset_n
);
wire sigmadelta_sample;
sigmadelta_sampler m_sdsampler(
.clk(clk),
.A(adc_A),
.B(adc_B),
.out(sigmadelta_sample)
);
assign adc_O = sigmadelta_sample;
// RC model, output is y_next_q15
// ------------------------------
reg signed [15:0] y_q15;
wire signed [15:0] x_q15 = sigmadelta_sample ? 16'sh7fff : 16'sh0000;
wire signed [15:0] e_q15 = x_q15 - y_q15;
wire signed [31:0] prod_q30 = $signed(16'sh0b00) * $signed(e_q15); // factor should be 0b3b, used bit simplified here
wire signed [15:0] delta_q15 = prod_q30 >>> 15;
wire signed [15:0] y_next_q15 = y_q15 + delta_q15;
// Optional clamp to [0, 0x7FFF] (keeps GTKWave tidy)
function signed [15:0] clamp01_q15(input signed [15:0] v);
if (v < 16'sd0000) clamp01_q15 = 16'sd0000;
else if (v > 16'sh7FFF) clamp01_q15 = 16'sh7FFF;
else clamp01_q15 = v;
endfunction
always @(posedge clk or negedge reset_n) begin
if (!reset_n) y_q15 <= 16'sd0000;
else y_q15 <= clamp01_q15(y_next_q15);
end
// ------------------------------
endmodule

24
HW/sigmadelta_sampler.v Normal file
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@@ -0,0 +1,24 @@
`timescale 1ns/1ps
module sigmadelta_sampler(
input wire clk,
input wire A,
input wire B,
output wire out
);
wire O;
reg out_r;
TLVDS_IBUF m_cmp(
.I(A),
.IB(B),
.O(O)
);
always @(posedge clk) begin
out_r = O;
end
assign out = out_r;
endmodule

16
HW/toplevel.v
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@@ -3,23 +3,35 @@
module toplevel(
input wire clk,
input wire reset_n,
input wire button,
output wire led
output wire led,
input wire adc1_A,
input wire adc1_B,
output wire adc1_O
);
reg led_v;
wire led_i;
wire clk_120;
wire clk_15;
gw_pllvr m_pll(
.clkout(clk_120),
.reset(!reset_n),
.clkin(clk)
);
gw_clkdiv8 m_clkdiv8(
.clkout(clk_15),
.hclkin(clk_120),
.resetn(reset_n)
);
always @(posedge clk_120 or negedge reset_n) begin
if (!reset_n) begin
led_v <= 1'b0;
end else begin
led_v <= button;
led_v <= led_i;
end
end
assign led = led_v;

12
IP/gw_clkdiv8/gw_clkdiv8.ipc Normal file
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@@ -0,0 +1,12 @@
[General]
file=gw_clkdiv8
ipc_version=4
module=gw_clkdiv8
target_device=gw1nsr4c-009
type=clock_clkdiv
version=1.0
[Config]
Calibration=false
Division_Factor=8
Language=0

14
IP/gw_clkdiv8/gw_clkdiv8.mod Normal file
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@@ -0,0 +1,14 @@
-series GW1NSR
-device GW1NSR-4C
-device_version
-package QFN48P
-part_number GW1NSR-LV4CQN48PC7/I6
-mod_name gw_clkdiv8
-file_name gw_clkdiv8
-path /data/joppe/projects/modem/IP/gowin_clkdiv/
-type CLKDIV
-file_type vlg
-division_factor 8
-calib false

29
IP/gw_clkdiv8/gw_clkdiv8.v Normal file
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@@ -0,0 +1,29 @@
//Copyright (C)2014-2025 Gowin Semiconductor Corporation.
//All rights reserved.
//File Title: IP file
//Tool Version: V1.9.12
//Part Number: GW1NSR-LV4CQN48PC7/I6
//Device: GW1NSR-4C
//Created Time: Wed Oct 1 18:23:11 2025
module gw_clkdiv8 (clkout, hclkin, resetn);
output clkout;
input hclkin;
input resetn;
wire gw_gnd;
assign gw_gnd = 1'b0;
CLKDIV clkdiv_inst (
.CLKOUT(clkout),
.HCLKIN(hclkin),
.RESETN(resetn),
.CALIB(gw_gnd)
);
defparam clkdiv_inst.DIV_MODE = "8";
defparam clkdiv_inst.GSREN = "false";
endmodule //gw_clkdiv8

18
IP/gw_clkdiv8/gw_clkdiv8_tmp.v Normal file
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@@ -0,0 +1,18 @@
//Copyright (C)2014-2025 Gowin Semiconductor Corporation.
//All rights reserved.
//File Title: Template file for instantiation
//Tool Version: V1.9.12
//Part Number: GW1NSR-LV4CQN48PC7/I6
//Device: GW1NSR-4C
//Created Time: Wed Oct 1 18:23:11 2025
//Change the instance name and port connections to the signal names
//--------Copy here to design--------
gw_clkdiv8 your_instance_name(
.clkout(clkout), //output clkout
.hclkin(hclkin), //input hclkin
.resetn(resetn) //input resetn
);
//--------Copy end-------------------

27
SIM/sampling_tb.v Normal file
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@@ -0,0 +1,27 @@
`timescale 1ns/1ps
module sampling_tb;
reg clk;
reg reset_n;
sampling m_sampling(
.clk(clk),
.reset_n(reset_n)
);
initial begin
$dumpfile("sampling_tb.vcd");
$dumpvars (0, sampling_tb);
clk <= 1'b0;
reset_n <= 1'b0;
#50 reset_n <= 1'b1;
#1000000
$finish;
end
//15 MHz clock
always #33.33 clk = ~clk;
endmodule

106
SIM/sigmadelta_sampler.v Normal file
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@@ -0,0 +1,106 @@
`timescale 1ns/1ps
module sigmadelta_sampler(
input wire clk,
input wire A,
input wire B,
output wire out
);
// ===== Tunable parameters =====
// Sine source (A input / P)
parameter real F_HZ = 2.0e3; // input sine frequency (1 kHz)
parameter real AMP = 1.5; // sine amplitude (V)
parameter real VCM = 1.65; // common-mode (V), centered in 0..3.3V
// Comparator behavior
parameter real VTH = 0.0; // threshold on (vp - vn)
parameter real VHYST = 0.05; // symmetric hysteresis half-width (V)
parameter integer ADD_HYST = 0; // 1 to enable hysteresis
// 1-bit DAC rails (feedback into RC)
parameter real VLOW = 0.0; // DAC 0 (V)
parameter real VHIGH = 3.3; // DAC 1 (V)
// RC filter (B input / N)
parameter real R_OHMS = 3300.0; // 3.3k
parameter real C_FARADS = 220e-12; // 220 pF
// Integration step (ties to `timescale`)
parameter integer TSTEP_NS = 10; // sim step in ns (choose << tau)
// ===== Internal state (simulation only) =====
real vp, vn; // comparator A/B inputs
real v_rc; // RC node voltage (== vn)
real v_dac; // DAC output voltage from O
real t_s; // time in seconds
real dt_s; // step in seconds
real tau_s; // R*C time constant in seconds
real two_pi;
reg q; // comparator latched output (pre-delay)
reg O;
reg sampler;
initial sampler <= 1'b0;
always @(posedge clk) begin
sampler <= O;
end
assign out = sampler;
// Helper task: update comparator with optional hysteresis
task automatic comp_update;
real diff;
begin
diff = (vp - vn);
if (ADD_HYST != 0) begin
// simple symmetric hysteresis around VTH
if (q && (diff < (VTH - VHYST))) q = 1'b0;
else if (!q && (diff > (VTH + VHYST))) q = 1'b1;
// else hold
end else begin
q = (diff > VTH) ? 1'b1 : 1'b0;
end
end
endtask
initial begin
// Init constants
two_pi = 6.283185307179586;
tau_s = R_OHMS * C_FARADS; // ~7.26e-7 s
dt_s = TSTEP_NS * 1.0e-9;
// Init states
t_s = 0.0;
q = 1'b0; // start low
O = 1'b0;
v_dac= VLOW;
v_rc = (VHIGH + VLOW)/2.0; // start mid-rail to reduce start-up transient
vn = v_rc;
vp = VCM;
// Main sim loop
forever begin
#(TSTEP_NS); // advance discrete time step
t_s = t_s + dt_s;
// 1) Update DAC from previous comparator state
v_dac = sampler ? VHIGH : VLOW;
// 2) RC low-pass driven by DAC: Euler step
// dv = (v_dac - v_rc) * dt/tau
v_rc = v_rc + (v_dac - v_rc) * (dt_s / tau_s);
vn = v_rc;
// 3) Input sine on A
vp = VCM + AMP * $sin(two_pi * F_HZ * t_s);
// 4) Comparator decision (with optional hysteresis)
comp_update();
// 5) Output with propagation delay
O = q;
end
end
endmodule

11
SIM/toplevel_tb.v
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@@ -9,8 +9,12 @@ module toplevel_tb;
toplevel m_toplevel(
.clk(clk),
.reset_n(reset_n),
.button(button),
.led(led)
.led(led),
.adc1_A(1'b0),
.adc1_B(1'b0)
);
initial begin
@@ -30,11 +34,11 @@ module toplevel_tb;
#185 button <= 1'b0;
#400
#2000000
$finish;
end
always #37 clk = ~clk;
always #18.5 clk = ~clk;
// Simulation stuff
// PLL quickstart
@@ -47,6 +51,7 @@ module toplevel_tb;
force toplevel_tb.m_toplevel.m_pll.pllvr_inst.LOCK = 1'b1;
force toplevel_tb.m_toplevel.m_pll.pllvr_inst.CLKOUT = tb_pll_clk;
force toplevel_tb.m_toplevel.m_pll.pllvr_inst.CLKOUTP = tb_pll_clk;
force toplevel_tb.m_toplevel.m_pll.pllvr_inst.RESET = 1'b1;
end
`endif
// SDF annotation

2
modem.gprj
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@@ -5,7 +5,9 @@
<Version>5</Version>
<Device name="GW1NSR-4C" pn="GW1NSR-LV4CQN48PC7/I6">gw1nsr4c-009</Device>
<FileList>
<File path="HW/sigmadelta_sampler.v" type="file.verilog" enable="1"/>
<File path="HW/toplevel.v" type="file.verilog" enable="1"/>
<File path="IP/gw_clkdiv8/gw_clkdiv8.v" type="file.verilog" enable="1"/>
<File path="IP/gw_pllvr/gw_pllvr.v" type="file.verilog" enable="1"/>
<File path="CON/io.cst" type="file.cst" enable="1"/>
<File path="CON/timing.sdc" type="file.sdc" enable="1"/>

4
modem.gprj.user
View File

@@ -22,6 +22,6 @@
<ResultFile ResultFileType="RES.syn.report" ResultFilePath="impl/gwsynthesis/modem_syn.rpt.html"/>
<ResultFile ResultFileType="RES.syn.resource" ResultFilePath="impl/gwsynthesis/modem_syn_rsc.xml"/>
</ResultFileList>
<Ui></Ui>
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</UserConfig>

1
scripts/program.sh Executable file
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@@ -0,0 +1 @@
openFPGALoader impl/pnr/modem.fs

0
scripts/run_all.tcl Normal file → Executable file
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12
scripts/run_sim.sh
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@@ -6,10 +6,18 @@
cvc +acc \
+show_canceled_e +suppress_warns+653+3102 \
-v SIM/prim_tsim.v \
+define+FAST_PLL_SIM \
-v SIM/prim_tsim.v \
\
IP/gw_pllvr/gw_pllvr.v \
IP/gw_clkdiv8/gw_clkdiv8.v \
HW/toplevel.v \
SIM/toplevel_tb.v \
HW/sampling.v \
\
SIM/sigmadelta_sampler.v \
\
SIM/sampling_tb.v \
SIM/globals.v \
+librescan
./cvcsim
# SIM/toplevel_tb.v \