tt05_dffram_test.py

tt05_dffram_test.py

# SPDX-License-Identifier: Apache-2.0
# Copyright (C) 2024, Uri Shaked

from ttboard.demoboard import DemoBoard
from ttboard.mode import RPMode
import random
from machine import Pin

WRITE_EN = 0x80


class DFFRAM:
    def __init__(self, tt):
        self.tt = tt
        tt.shuttle.tt_um_urish_dffram.enable()
        tt.bidir_mode = [Pin.OUT] * 8
        tt.clock_project_stop()
        tt.project_clk(False)
        tt.reset_project(True)
        tt.clock_project_once()
        tt.reset_project(False)

    def write(self, addr, value):
        self.tt.bidir_byte = value
        self.tt.input_byte = (addr & 0x7F) | WRITE_EN
        self.tt.clock_project_once() # Write happens on the falling edge of the clock?
        self.tt.project_clk(True)
        self.tt.input_byte = 0    # Disable write
        self.tt.project_clk(False)

    def read(self, addr):
        self.tt.input_byte = addr
        self.tt.clock_project_once()
        return self.tt.output_byte


def shuffle(array):
    """Shuffle an array in place"""
    for i in range(len(array) - 1, 0, -1):
        j = random.randrange(i + 1)
        array[i], array[j] = array[j], array[i]
    return array


def run():
    tt = DemoBoard.get()
    tt.mode = RPMode.ASIC_RP_CONTROL
    dffram = DFFRAM(tt)

    print("Writing 128 bytes")
    for i in range(128):
        dffram.write(i, i ^ 0x42)

    print("Verifying 128 bytes")
    for i in range(128):
        assert dffram.read(i) == i ^ 0x42

    print("Writing 128 random bytes")
    random_bytes = [random.randint(0, 255) for _ in range(128)]
    random_offsets = shuffle(list(range(128)))
    for i in random_offsets:
        dffram.write(i, random_bytes[i])

    print("Verifying 128 random bytes")
    for i in range(128):
        assert dffram.read(i) == random_bytes[i]

    print("All tests passed")


run()