cocotb: Test and fix 1khz sine

2 files changed, 45 insertions, 24 deletions

diff --git a/cocotb_try/cic3_pdm.v b/cocotb_try/cic3_pdm.v
index 1c8ba25..e350fda 100644
--- a/cocotb_try/cic3_pdm.v
+++ b/cocotb_try/cic3_pdm.v
@@ -7,10 +7,11 @@ module cic3_pdm (
     input  wire        pdm_in,     // 1-bit PDM data input
     output wire signed [15:0] pcm_out, // Decimated PCM output
     output wire        pcm_valid,   // High when pcm_out is valid       
-    output reg        pdm_out
+    output reg         pdm_out
 
 );
     parameter DECIMATION = 64; // Decimation factor
+    parameter OUTPUT_SHIFT = 8; // Can tune this
 
     // Internal registers
     reg signed [31:0] integrator_0 = 0;
@@ -60,7 +61,7 @@ module cic3_pdm (
 
             // Bit-shift down to get 16-bit output (tune shift based on DECIMATION and stage count)
             pdm_out <= pdm_in;
-            pcm_out_r <= comb_2[31:16]; 
+            pcm_out_r <= comb_2[OUTPUT_SHIFT + 15 : OUTPUT_SHIFT];
             pcm_valid_r <= 1;
         end
     end
diff --git a/cocotb_try/test_cic.py b/cocotb_try/test_cic.py
index 19a17f9..ea176fc 100644
--- a/cocotb_try/test_cic.py
+++ b/cocotb_try/test_cic.py
@@ -5,46 +5,66 @@
 import cocotb
 from cocotb.triggers import FallingEdge, RisingEdge, Timer, with_timeout
 from cocotb.clock import Clock
+from cocotb.binary import BinaryValue
 
+import numpy
 
-async def generate_clock(dut):
-    """Generate clock pulses."""
+from pcm2pdm import convert
+from testsignal import generate_test_tone
+from test_pdm import plot_reconstruct
 
-    for cycle in range(10):
-        dut.clk.value = 0
-        await Timer(1, units="ns")
-        dut.clk.value = 1
-        await Timer(1, units="ns")
 
 async def drive_waveform(dut, waveform):
+
+    high_delay = Timer(1, units="ns")
+    low_delay = Timer(1, units="ns")
+
     for a_val in waveform:
-        dut.pdm_in.value = a_val
+        dut.pdm_in.value = bool(a_val)
+
+        #dut.clk.value = 0
+        #await low_delay
+        #dut.clk.value = 1
+        #await high_delay
+
         await RisingEdge(dut.clk)
 
 
+async def collect_output(dut, samples):
+
+    out = numpy.zeros(samples, dtype=numpy.int16)
+
+    # wait for the PCM output
+    for i in range(samples):
+        await with_timeout(RisingEdge(dut.pcm_valid), 100000, 'ns')
+        #dut._log.info("PCM is %s", dut.pcm_out.value)
+        s = dut.pcm_out.value.signed_integer
+        out[i] = s
+
+    return out
+
+
 @cocotb.test()
 async def my_second_test(dut):
     """Try running with PDM input"""
 
-    #dut.rst.value = 1
-    #await RisingEdge(dut.clk)
-    #dut.rst.value = 0
-
-    pcm_samples = 10
+    sr = 16000
     decimation = 64
-    pdm_data = [0, 0, 1] * (pcm_samples*decimation)
+
+    sig = generate_test_tone(duration_sec=0.004,
+        freqs=[1000.0], noise_level=0.0, sample_rate=sr, amplitude=0.9,
+    )
+
+    pdm_data = convert(sig)
 
     cocotb.start_soon(Clock(dut.clk, 10, units="ns").start())
     cocotb.start_soon(drive_waveform(dut, pdm_data))
 
-    # wait for the PCM output
-    for _ in range(pcm_samples):
-        await with_timeout(RisingEdge(dut.pcm_valid), 100000, 'ns')
-        dut._log.info("PCM is %s", dut.pcm_out.value)
+    pcm_samples = len(pdm_data)//decimation
+    output = await collect_output(dut, pcm_samples)
 
-    #dut._log.info("pdm_out is %s", dut.pdm_out.value)
-    #assert dut.pdm_out.value == 1
+    output = output / 1024
 
-    dut._log.info("my_signal_1 is %s", dut.pcm_out.value)
-    assert dut.pcm_out.value == 1212
+    fig = plot_reconstruct(sig, pdm_data, output, sr=sr, aspect=6.0)
+    fig.savefig('pdm_cocotb.png')