FIFOBus.py

class FIFOBus(object):
    def __init__(self, size=16, width=8):
        """
        """
        self.name = "fifobus{0}".format(_fb_num)

        # @todo: add write clock and read clock to the interface!
        # @todo: use longer names read, read_valid, read_data,
        # @todo: write, write_data, etc.!

        # all the data signals are from the perspective
        # of the FIFO being interfaced to.        
        self.clear = Signal(bool(0))           # fifo clear
        #self.wclk = None                      # write side clock
        self.write = Signal(bool(0))              # write strobe to fifo
        self.write_data = Signal(intbv(0)[width:])  # fifo data in

        #self.rclk = None                      # read side clock
        self.read = Signal(bool(0))              # fifo read strobe
        self.read_data = Signal(intbv(0)[width:])  # fifo data out
        self.read_valid = Signal(bool(0))
        self.empty = Signal(bool(1))           # fifo empty
        self.full = Signal(bool(0))            # fifo full
        self.count = Signal(intbv(0, min=0, max=size+1))

        self.width = width
        self.size = size

        _add_bus(self, self.name)
        
    def __str__(self):
        s = "wr: {} {:04X}, rd: {} {:04X}, empty {}, full {}".format(
            int(self.write), int(self.write_data), int(self.read), int(self.read_data),
            int(self.empty), int(self.full))
        return s
        
    def assign_read_write_paths(self, readpath, writepath):
        """
        Assign the signals from the `readpath` to the read signals
        of this interface and same for write
        """
        assert isinstance(readpath, FIFOBus)
        assert isinstance(writepath, FIFOBUus)
        
        @always_comb
        def beh_assign():
            readpath.read_data.next = self.read_data
            self.read.next = readpath.read
            
            self.write_data.next = writepath.write_data
            self.write.next = writepath.write