57 lines
1.5 KiB
Python
57 lines
1.5 KiB
Python
# SPDX-License-Identifier: AGPL-3.0-Only
|
|
# Copyright (C) 2023 Sean Anderson <seanga2@gmail.com>
|
|
|
|
import cocotb
|
|
from cocotb.binary import BinaryValue
|
|
from cocotb.clock import Clock
|
|
from cocotb.triggers import FallingEdge, Timer
|
|
from cocotb.utils import get_sim_time, get_sim_steps
|
|
|
|
from .axis_replay_buffer import send_packet
|
|
|
|
BAUD = 4e6
|
|
BIT_STEPS = get_sim_steps(1 / BAUD, 'sec', round_mode='round')
|
|
|
|
@cocotb.test(timeout_time=1, timeout_unit='ms')
|
|
async def test_tx(uart):
|
|
uart.clk.value = BinaryValue('Z')
|
|
uart.valid.value = 0
|
|
uart.high_speed.value = BAUD == 4e6
|
|
|
|
await Timer(1)
|
|
await cocotb.start(Clock(uart.clk, 8, units='ns').start())
|
|
await FallingEdge(uart.clk)
|
|
|
|
msg = b"Hello"
|
|
|
|
await cocotb.start(send_packet({
|
|
'clk': uart.clk,
|
|
'data': uart.data,
|
|
'valid': uart.valid,
|
|
'ready': uart.ready,
|
|
}, msg))
|
|
|
|
async def getchar():
|
|
while not uart.tx.value:
|
|
await FallingEdge(uart.clk)
|
|
while uart.tx.value:
|
|
await FallingEdge(uart.clk)
|
|
await Timer(BIT_STEPS // 2)
|
|
|
|
result = 0
|
|
for _ in range(8):
|
|
await Timer(BIT_STEPS)
|
|
result >>= 1
|
|
result |= 0x80 if uart.tx.value else 0
|
|
|
|
return result
|
|
|
|
then = get_sim_time()
|
|
for c in msg:
|
|
assert c == await getchar()
|
|
now = get_sim_time()
|
|
|
|
expected = BIT_STEPS * (10 * len(msg) - 1.5)
|
|
actual = now - then
|
|
assert abs(actual - expected) / expected < 0.01
|