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https://github.com/corundum/corundum.git
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Improve PTP CDC module testbench
Signed-off-by: Alex Forencich <alex@alexforencich.com>
This commit is contained in:
Alex Forencich
parent
5a37442706
commit
f9ae6da8bd
@ -25,7 +25,7 @@ THE SOFTWARE.
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// Language: Verilog 2001
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`resetall
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`timescale 1ns / 1ps
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`timescale 1ns / 1fs
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`default_nettype none
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/*
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@ -24,7 +24,7 @@ SIM ?= icarus
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WAVES ?= 0
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COCOTB_HDL_TIMEUNIT = 1ns
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COCOTB_HDL_TIMEPRECISION = 1ps
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COCOTB_HDL_TIMEPRECISION = 1fs
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DUT = ptp_clock_cdc
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TOPLEVEL = $(DUT)
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@ -1,7 +1,7 @@
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#!/usr/bin/env python
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"""
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Copyright (c) 2020 Alex Forencich
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Copyright (c) 2020-2023 Alex Forencich
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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@ -25,6 +25,7 @@ THE SOFTWARE.
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import logging
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import os
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from statistics import mean, stdev
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import pytest
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import cocotb_test.simulator
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@ -32,7 +33,7 @@ import cocotb_test.simulator
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import cocotb
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from cocotb.clock import Clock
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from cocotb.triggers import RisingEdge, Timer
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from cocotb.utils import get_sim_steps
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from cocotb.utils import get_sim_steps, get_sim_time
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from cocotbext.eth import PtpClock
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@ -44,9 +45,7 @@ class TB:
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self.log = logging.getLogger("cocotb.tb")
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self.log.setLevel(logging.DEBUG)
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cocotb.start_soon(Clock(dut.input_clk, 6.4, units="ns").start())
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cocotb.start_soon(Clock(dut.sample_clk, 10, units="ns").start())
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cocotb.start_soon(Clock(dut.sample_clk, 9.9, units="ns").start())
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if len(dut.input_ts) == 64:
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self.ptp_clock = PtpClock(
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@ -65,8 +64,13 @@ class TB:
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period_ns=6.4
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)
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self._clock_cr = None
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self.set_output_clock_period(6.4)
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self.input_clock_period = 6.4
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dut.input_clk.setimmediatevalue(0)
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cocotb.start_soon(self._run_input_clock())
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self.output_clock_period = 6.4
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dut.output_clk.setimmediatevalue(0)
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cocotb.start_soon(self._run_output_clock())
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async def reset(self):
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self.dut.input_rst.setimmediatevalue(0)
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@ -82,17 +86,33 @@ class TB:
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for k in range(10):
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await RisingEdge(self.dut.input_clk)
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def set_output_clock_period(self, period):
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if self._clock_cr is not None:
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self._clock_cr.kill()
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def set_input_clock_period(self, period):
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self.input_clock_period = period
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self._clock_cr = cocotb.start_soon(self._run_clock(period))
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async def _run_clock(self, period):
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half_period = get_sim_steps(period / 2.0, 'ns')
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t = Timer(half_period)
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async def _run_input_clock(self):
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period = None
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steps_per_ns = get_sim_steps(1.0, 'ns')
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while True:
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if period != self.input_clock_period:
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period = self.input_clock_period
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t = Timer(int(steps_per_ns * period / 2.0))
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await t
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self.dut.input_clk.value = 1
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await t
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self.dut.input_clk.value = 0
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def set_output_clock_period(self, period):
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self.output_clock_period = period
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async def _run_output_clock(self):
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period = None
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steps_per_ns = get_sim_steps(1.0, 'ns')
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while True:
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if period != self.output_clock_period:
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period = self.output_clock_period
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t = Timer(int(steps_per_ns * period / 2.0))
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await t
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self.dut.output_clk.value = 1
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await t
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@ -112,14 +132,45 @@ class TB:
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else:
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return (ts >> 48) + ((ts & 0xffffffffffff)/2**16*1e-9)
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async def measure_ts_diff(self, N=1000):
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total = 0
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async def measure_ts_diff(self, N=100):
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input_ts_lst = []
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output_ts_lst = []
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async def collect_timestamps(clk, get_ts, lst):
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while True:
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await RisingEdge(clk)
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lst.append((get_sim_time('sec'), get_ts()))
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input_cr = cocotb.start_soon(collect_timestamps(self.dut.input_clk, self.get_input_ts_ns, input_ts_lst))
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output_cr = cocotb.start_soon(collect_timestamps(self.dut.output_clk, self.get_output_ts_ns, output_ts_lst))
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for k in range(N):
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input_ts_ns = self.get_input_ts_ns()
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output_ts_ns = self.get_output_ts_ns()
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total += input_ts_ns-output_ts_ns
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await Timer(100, 'ps')
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return total/N
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await RisingEdge(self.dut.output_clk)
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input_cr.kill()
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output_cr.kill()
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diffs = []
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its1 = input_ts_lst.pop(0)
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its2 = input_ts_lst.pop(0)
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for ots in output_ts_lst:
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while its2[0] < ots[0] and input_ts_lst:
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its1 = its2
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its2 = input_ts_lst.pop(0)
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if its2[0] < ots[0]:
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break
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dt = its2[0] - its1[0]
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dts = its2[1] - its1[1]
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its = its1[1]+dts/dt*(ots[0]-its1[0])
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diffs.append(ots[1] - its)
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return diffs
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@cocotb.test()
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@ -132,90 +183,236 @@ async def run_test(dut):
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await RisingEdge(dut.input_clk)
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tb.log.info("Same clock speed")
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tb.set_input_clock_period(6.4)
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tb.set_output_clock_period(6.4)
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await RisingEdge(dut.input_clk)
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for i in range(40000):
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for i in range(100000):
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await RisingEdge(dut.input_clk)
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assert tb.dut.locked.value.integer
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diff = await tb.measure_ts_diff()*1e9
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tb.log.info(f"Difference: {diff} ns")
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assert abs(diff) < 10
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diffs = await tb.measure_ts_diff()
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tb.log.info(f"Difference: {mean(diffs)*1e9} ns (stdev: {stdev(diffs)*1e9})")
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assert abs(mean(diffs)*1e9) < 5
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await RisingEdge(dut.input_clk)
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tb.log.info("Slightly faster")
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tb.log.info("10 ppm slower")
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tb.set_output_clock_period(6.2)
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tb.set_input_clock_period(6.4)
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tb.set_output_clock_period(6.4*(1+.00001))
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await RisingEdge(dut.input_clk)
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for i in range(40000):
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for i in range(100000):
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await RisingEdge(dut.input_clk)
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assert tb.dut.locked.value.integer
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diff = await tb.measure_ts_diff()*1e9
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tb.log.info(f"Difference: {diff} ns")
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assert abs(diff) < 10
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diffs = await tb.measure_ts_diff()
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tb.log.info(f"Difference: {mean(diffs)*1e9} ns (stdev: {stdev(diffs)*1e9})")
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assert abs(mean(diffs)*1e9) < 5
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await RisingEdge(dut.input_clk)
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tb.log.info("Slightly slower")
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tb.log.info("10 ppm faster")
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tb.set_output_clock_period(6.6)
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tb.set_input_clock_period(6.4)
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tb.set_output_clock_period(6.4*(1-.00001))
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await RisingEdge(dut.input_clk)
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for i in range(40000):
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for i in range(100000):
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await RisingEdge(dut.input_clk)
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assert tb.dut.locked.value.integer
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diff = await tb.measure_ts_diff()*1e9
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tb.log.info(f"Difference: {diff} ns")
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assert abs(diff) < 10
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diffs = await tb.measure_ts_diff()
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tb.log.info(f"Difference: {mean(diffs)*1e9} ns (stdev: {stdev(diffs)*1e9})")
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assert abs(mean(diffs)*1e9) < 5
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await RisingEdge(dut.input_clk)
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tb.log.info("Significantly faster")
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tb.log.info("200 ppm slower")
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tb.set_input_clock_period(6.4)
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tb.set_output_clock_period(6.4*(1+.0002))
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await RisingEdge(dut.input_clk)
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for i in range(100000):
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await RisingEdge(dut.input_clk)
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assert tb.dut.locked.value.integer
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diffs = await tb.measure_ts_diff()
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tb.log.info(f"Difference: {mean(diffs)*1e9} ns (stdev: {stdev(diffs)*1e9})")
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assert abs(mean(diffs)*1e9) < 5
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await RisingEdge(dut.input_clk)
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tb.log.info("200 ppm faster")
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tb.set_input_clock_period(6.4)
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tb.set_output_clock_period(6.4*(1-.0002))
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await RisingEdge(dut.input_clk)
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for i in range(100000):
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await RisingEdge(dut.input_clk)
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assert tb.dut.locked.value.integer
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diffs = await tb.measure_ts_diff()
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tb.log.info(f"Difference: {mean(diffs)*1e9} ns (stdev: {stdev(diffs)*1e9})")
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assert abs(mean(diffs)*1e9) < 5
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await RisingEdge(dut.input_clk)
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tb.log.info("Coherent tracking (+/- 10 ppm)")
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tb.set_input_clock_period(6.4)
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tb.set_output_clock_period(6.4)
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await RisingEdge(dut.input_clk)
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period = 6.400
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step = 0.000002
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period_min = 6.4*(1-.00001)
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period_max = 6.4*(1+.00001)
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for i in range(500):
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period += step
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if period <= period_min:
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step = abs(step)
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if period >= period_max:
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step = -abs(step)
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tb.set_output_clock_period(period)
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for i in range(200):
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await RisingEdge(dut.input_clk)
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assert tb.dut.locked.value.integer
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diffs = await tb.measure_ts_diff()
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tb.log.info(f"Difference: {mean(diffs)*1e9} ns (stdev: {stdev(diffs)*1e9})")
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assert abs(mean(diffs)*1e9) < 5
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await RisingEdge(dut.input_clk)
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tb.log.info("Coherent tracking (+/- 200 ppm)")
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tb.set_input_clock_period(6.4)
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tb.set_output_clock_period(6.4)
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await RisingEdge(dut.input_clk)
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period = 6.400
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step = 0.000002
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period_min = 6.4*(1-.0002)
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period_max = 6.4*(1+.0002)
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for i in range(5000):
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period += step
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if period <= period_min:
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step = abs(step)
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if period >= period_max:
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step = -abs(step)
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tb.set_output_clock_period(period)
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for i in range(20):
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await RisingEdge(dut.input_clk)
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assert tb.dut.locked.value.integer
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diffs = await tb.measure_ts_diff()
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tb.log.info(f"Difference: {mean(diffs)*1e9} ns (stdev: {stdev(diffs)*1e9})")
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assert abs(mean(diffs)*1e9) < 5
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await RisingEdge(dut.input_clk)
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tb.log.info("Slightly faster (6.3 ns)")
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tb.set_input_clock_period(6.4)
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tb.set_output_clock_period(6.3)
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await RisingEdge(dut.input_clk)
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for i in range(100000):
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await RisingEdge(dut.input_clk)
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assert tb.dut.locked.value.integer
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diffs = await tb.measure_ts_diff()
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tb.log.info(f"Difference: {mean(diffs)*1e9} ns (stdev: {stdev(diffs)*1e9})")
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assert abs(mean(diffs)*1e9) < 5
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await RisingEdge(dut.input_clk)
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tb.log.info("Slightly slower (6.5 ns)")
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tb.set_input_clock_period(6.4)
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tb.set_output_clock_period(6.5)
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await RisingEdge(dut.input_clk)
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for i in range(100000):
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await RisingEdge(dut.input_clk)
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assert tb.dut.locked.value.integer
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diffs = await tb.measure_ts_diff()
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tb.log.info(f"Difference: {mean(diffs)*1e9} ns (stdev: {stdev(diffs)*1e9})")
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assert abs(mean(diffs)*1e9) < 5
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await RisingEdge(dut.input_clk)
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tb.log.info("Significantly faster (250 MHz)")
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tb.set_input_clock_period(6.4)
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tb.set_output_clock_period(4.0)
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await RisingEdge(dut.input_clk)
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for i in range(40000):
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for i in range(100000):
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await RisingEdge(dut.input_clk)
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assert tb.dut.locked.value.integer
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diff = await tb.measure_ts_diff()*1e9
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tb.log.info(f"Difference: {diff} ns")
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assert abs(diff) < 10
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diffs = await tb.measure_ts_diff()
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tb.log.info(f"Difference: {mean(diffs)*1e9} ns (stdev: {stdev(diffs)*1e9})")
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assert abs(mean(diffs)*1e9) < 5
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await RisingEdge(dut.input_clk)
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tb.log.info("Significantly slower")
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tb.log.info("Significantly slower (100 MHz)")
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tb.set_input_clock_period(6.4)
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tb.set_output_clock_period(10.0)
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await RisingEdge(dut.input_clk)
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for i in range(30000):
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for i in range(100000):
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await RisingEdge(dut.input_clk)
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assert tb.dut.locked.value.integer
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diff = await tb.measure_ts_diff()*1e9
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diffs = await tb.measure_ts_diff()
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tb.log.info(f"Difference: {mean(diffs)*1e9} ns (stdev: {stdev(diffs)*1e9})")
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assert abs(mean(diffs)*1e9) < 5
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tb.log.info(f"Difference: {diff} ns")
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await RisingEdge(dut.input_clk)
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tb.log.info("Significantly faster (390.625 MHz)")
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assert abs(diff) < 10
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tb.set_input_clock_period(6.4)
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tb.set_output_clock_period(2.56)
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await RisingEdge(dut.input_clk)
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for i in range(100000):
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await RisingEdge(dut.input_clk)
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assert tb.dut.locked.value.integer
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diffs = await tb.measure_ts_diff()
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tb.log.info(f"Difference: {mean(diffs)*1e9} ns (stdev: {stdev(diffs)*1e9})")
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assert abs(mean(diffs)*1e9) < 5
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await RisingEdge(dut.input_clk)
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await RisingEdge(dut.input_clk)
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