Source code for hwtLib.logic.cntrGray

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

from hwt.code import If, binToGray
from hwt.hdl.constants import Time
from hwt.interfaces.std import Signal, VectSignal
from hwt.interfaces.utils import addClkRstn
from hwt.serializer.mode import serializeParamsUniq
from hwt.simulator.simTestCase import SimTestCase
from hwt.synthesizer.param import Param
from hwt.synthesizer.unit import Unit


[docs]@serializeParamsUniq
class GrayCntr(Unit):
[docs]    def _config(self):
        self.DATA_WIDTH = Param(4)
        self.INIT_VAL = Param(0)  # binary

[docs]    def _declr(self):
        addClkRstn(self)
        self.en = Signal()

        self.dataOut = VectSignal(self.DATA_WIDTH)

[docs]    def _impl(self):
        binCntr = self._reg("cntr_bin_reg", self.dataOut._dtype, self.INIT_VAL)

        self.dataOut(binToGray(binCntr))

        If(self.en,
           binCntr(binCntr + 1)
        )


[docs]class GrayCntrTC(SimTestCase):
[docs]    def test_count(self):
        u = GrayCntr()
        self.prepareUnit(u)
        u.en._ag.data.append(1)

        self.runSim(170 * Time.ns)
        self.assertValSequenceEqual(u.dataOut._ag.data,
                                    [
                                        0b0000,
                                        0b0001,
                                        0b0011,
                                        0b0010,
                                        0b0110,
                                        0b0111,
                                        0b0101,
                                        0b0100,
                                        0b1100,
                                        0b1101,
                                        0b1111,
                                        0b1110,
                                        0b1010,
                                        0b1011,
                                        0b1001,
                                        0b1000,
                                    ])


if __name__ == "__main__":
    import unittest
    suite = unittest.TestSuite()
    suite.addTest(unittest.makeSuite(GrayCntrTC))
    runner = unittest.TextTestRunner(verbosity=3)
    runner.run(suite)

    from hwt.synthesizer.utils import toRtl
    print(toRtl(GrayCntr()))