manta/test/test_uart_rx_sim.py

66 lines
1.7 KiB
Python

from amaranth.sim import Simulator
from manta.uart import UARTReceiver
from manta.utils import *
from random import sample
uart_rx = UARTReceiver(clocks_per_baud=10)
def verify_receive(data):
# 8N1 serial, LSB sent first
data_bits = "0" + f"{data:08b}"[::-1] + "1"
data_bits = [int(bit) for bit in data_bits]
valid_asserted_before = False
for i in range(10 * uart_rx.clocks_per_baud):
bit_index = i // uart_rx.clocks_per_baud
# Every cycle, run checks on uart_rx:
if (yield uart_rx.valid_o):
if (yield uart_rx.data_o) != data:
a = yield uart_rx.data_o
print(data_bits)
raise ValueError(
f"Incorrect byte presented - gave {hex(a)} instead of {hex(data)}!"
)
if bit_index != 9:
print(bit_index)
raise ValueError("Byte presented before it is complete!")
if not valid_asserted_before:
valid_asserted_before = True
else:
raise ValueError("Valid asserted more than once!")
yield uart_rx.rx.eq(data_bits[bit_index])
yield
if not valid_asserted_before:
raise ValueError("Failed to assert valid!")
def test_all_possible_bytes():
def testbench():
yield uart_rx.rx.eq(1)
yield
for i in range(0xFF):
yield from verify_receive(i)
simulate(uart_rx, testbench)
def test_bytes_random_sample():
def testbench():
yield uart_rx.rx.eq(1)
yield
for i in sample(range(0xFF), k=0xFF):
yield from verify_receive(i)
simulate(uart_rx, testbench)