saltylab-firmware/test/test_led.py
sl-firmware fbca191bae feat(firmware): WS2812B NeoPixel LED status indicator driver (Issue #193)
Implements TIM3_CH1 PWM driver for 8-LED NeoPixel ring with:
- 6 state-based animations: boot (blue chase), armed (solid green),
  error (red blink), low battery (yellow pulse), charging (green breathe),
  e_stop (red strobe)
- Non-blocking via 1 ms tick callback
- GRB byte order encoding (WS2812B standard)
- PWM duty values for "0" (~40%) and "1" (~56%) bit encoding
- 10 unit tests covering state transitions, animations, color encoding

Driver integrated into main.c initialization and main loop tick.
Includes buzzer driver (Issue #189) integration.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
2026-03-02 11:06:13 -05:00

345 lines
10 KiB
Python

"""
test_led.py — WS2812B NeoPixel LED driver tests (Issue #193)
Verifies in Python:
- State transitions: boot → armed, error, low_battery, charging, e_stop
- Animation timing: chase speed, blink/strobe frequency, pulse duration
- LED color encoding: RGB to GRB byte order, MSB-first bit encoding
- PWM duty values: bit "0" (~40%) and bit "1" (~56%) detection
- Animation sequencing: smooth transitions between states
- Sine wave lookup: breathing and pulse envelopes
"""
import pytest
# ── Constants ─────────────────────────────────────────────────────────────
NUM_LEDS = 8
BITS_PER_LED = 24 # RGB = 8 bits each
TOTAL_BITS = NUM_LEDS * BITS_PER_LED
PWM_PERIOD = 270 # 216 MHz / 800 kHz ≈ 270 (integer approximation)
BIT_0_DUTY = int(PWM_PERIOD * 40 / 100) # ~108 (40%)
BIT_1_DUTY = int(PWM_PERIOD * 56 / 100) # ~151 (56%)
# Animation periods (ms)
BOOT_CHASE_MS = 100 # ms per LED rotation
ERROR_BLINK_MS = 250
ESTOP_STROBE_MS = 125
PULSE_PERIOD_MS = 5120
# ── RGB Color Utility ─────────────────────────────────────────────────────
class RGBColor:
def __init__(self, r=0, g=0, b=0):
self.r = r
self.g = g
self.b = b
def __eq__(self, other):
return self.r == other.r and self.g == other.g and self.b == other.b
def __repr__(self):
return f"RGB({self.r},{self.g},{self.b})"
# ── WS2812B Encoding Utilities ────────────────────────────────────────────
def rgb_to_pwm_buffer(colors):
"""Encode LED colors into PWM duty values (GRB byte order, MSB first)."""
pwm_buf = []
for color in colors:
# GRB byte order (WS2812 standard)
bytes_grb = [color.g, color.r, color.b]
for byte in bytes_grb:
for bit in range(7, -1, -1):
bit_val = (byte >> bit) & 1
pwm_buf.append(BIT_1_DUTY if bit_val else BIT_0_DUTY)
return pwm_buf
def pwm_buffer_to_rgb(pwm_buf):
"""Decode PWM duty values back to RGB colors (for verification)."""
colors = []
for led_idx in range(NUM_LEDS):
base = led_idx * BITS_PER_LED
# GRB byte order
g = bytes_from_bits(pwm_buf[base : base + 8])
r = bytes_from_bits(pwm_buf[base + 8 : base + 16])
b = bytes_from_bits(pwm_buf[base + 16 : base + 24])
colors.append(RGBColor(r, g, b))
return colors
def bytes_from_bits(pwm_values):
"""Reconstruct a byte from PWM duty values."""
byte = 0
for pwm in pwm_values:
byte = (byte << 1) | (1 if pwm > (BIT_0_DUTY + BIT_1_DUTY) // 2 else 0)
return byte
# ── Sine Lookup ───────────────────────────────────────────────────────────
def sin_u8(phase):
"""Approximate sine wave (0-255) from phase (0-255)."""
# Simplified lookup (matching C implementation)
sine_lut = [
128, 131, 134, 137, 140, 143, 146, 149, 152, 155, 158, 161, 164, 167, 170, 173,
176, 179, 182, 185, 188, 191, 193, 196, 199, 201, 204, 206, 209, 211, 214, 216,
218, 221, 223, 225, 227, 229, 231, 233, 235, 236, 238, 240, 241, 243, 244, 245,
247, 248, 249, 250, 251, 252, 252, 253, 254, 254, 255, 255, 255, 255, 255, 254,
254, 253, 252, 252, 251, 250, 249, 248, 247, 245, 244, 243, 241, 240, 238, 236,
235, 233, 231, 229, 227, 225, 223, 221, 218, 216, 214, 211, 209, 206, 204, 201,
199, 196, 193, 191, 188, 185, 182, 179, 176, 173, 170, 167, 164, 161, 158, 155,
152, 149, 146, 143, 140, 137, 134, 131, 128, 125, 122, 119, 116, 113, 110, 107,
104, 101, 98, 95, 92, 89, 86, 83, 80, 77, 74, 71, 68, 65, 62, 59,
56, 53, 50, 47, 44, 41, 39, 36, 33, 31, 28, 26, 23, 21, 18, 16,
14, 11, 9, 7, 5, 3, 1, 0,
]
return sine_lut[phase % 256] if phase < len(sine_lut) else sine_lut[255]
# ── LED State Machine Simulator ───────────────────────────────────────────
class LEDSimulator:
def __init__(self):
self.leds = [RGBColor() for _ in range(NUM_LEDS)]
self.pwm_buf = [0] * TOTAL_BITS
self.current_state = 'BOOT'
self.next_state = 'BOOT'
self.state_start_ms = 0
def set_state(self, state):
self.next_state = state
def tick(self, now_ms):
# State transition
if self.next_state != self.current_state:
self.current_state = self.next_state
self.state_start_ms = now_ms
elapsed = now_ms - self.state_start_ms
# Run animation
if self.current_state == 'BOOT':
self._animate_boot(elapsed)
elif self.current_state == 'ARMED':
self._animate_armed()
elif self.current_state == 'ERROR':
self._animate_error(elapsed)
elif self.current_state == 'LOW_BATT':
self._animate_low_battery(elapsed)
elif self.current_state == 'CHARGING':
self._animate_charging(elapsed)
elif self.current_state == 'ESTOP':
self._animate_estop(elapsed)
# Encode to PWM buffer
self.pwm_buf = rgb_to_pwm_buffer(self.leds)
def _animate_boot(self, elapsed):
for i in range(NUM_LEDS):
self.leds[i] = RGBColor()
led_idx = (elapsed // BOOT_CHASE_MS) % NUM_LEDS
self.leds[led_idx] = RGBColor(b=255)
def _animate_armed(self):
for i in range(NUM_LEDS):
self.leds[i] = RGBColor(g=200)
def _animate_error(self, elapsed):
on = ((elapsed // ERROR_BLINK_MS) % 2) == 0
for i in range(NUM_LEDS):
self.leds[i] = RGBColor(r=255 if on else 0)
def _animate_low_battery(self, elapsed):
phase = (elapsed // 20) & 0xFF
brightness = sin_u8(phase)
val = (brightness * 255) >> 8
for i in range(NUM_LEDS):
self.leds[i] = RGBColor(r=val, g=val)
def _animate_charging(self, elapsed):
phase = (elapsed // 20) & 0xFF
brightness = sin_u8(phase)
val = (brightness * 255) >> 8
for i in range(NUM_LEDS):
self.leds[i] = RGBColor(g=val)
def _animate_estop(self, elapsed):
on = ((elapsed // ESTOP_STROBE_MS) % 2) == 0
for i in range(NUM_LEDS):
self.leds[i] = RGBColor(r=255 if on else 0)
# ── Tests ──────────────────────────────────────────────────────────────────
def test_state_transitions():
"""LED state should transition correctly."""
sim = LEDSimulator()
assert sim.current_state == 'BOOT'
sim.set_state('ARMED')
sim.tick(0)
assert sim.current_state == 'ARMED'
sim.set_state('ERROR')
sim.tick(1)
assert sim.current_state == 'ERROR'
def test_boot_chase_timing():
"""Boot state: LED should rotate every 100 ms."""
sim = LEDSimulator()
sim.set_state('BOOT')
# t=0: LED 0 should be blue
sim.tick(0)
assert sim.leds[0].b > 0
for i in range(1, NUM_LEDS):
assert sim.leds[i].b == 0
# t=100: LED 1 should be blue
sim.tick(100)
assert sim.leds[1].b > 0
for i in range(NUM_LEDS):
if i != 1:
assert sim.leds[i].b == 0
def test_armed_solid_green():
"""Armed state: all LEDs should be solid green."""
sim = LEDSimulator()
sim.set_state('ARMED')
sim.tick(0)
for led in sim.leds:
assert led.g > 0
assert led.r == 0
assert led.b == 0
def test_error_blinking():
"""Error state: LEDs should blink red every 250 ms."""
sim = LEDSimulator()
sim.set_state('ERROR')
# t=0-249: red on
sim.tick(0)
for led in sim.leds:
assert led.r > 0
# t=250-499: red off
sim.tick(250)
for led in sim.leds:
assert led.r == 0
# t=500-749: red on again
sim.tick(500)
for led in sim.leds:
assert led.r > 0
def test_low_battery_pulsing():
"""Low battery: LEDs should pulse yellow with sine envelope."""
sim = LEDSimulator()
sim.set_state('LOW_BATT')
# Sample at different points
sim.tick(0)
v0 = sim.leds[0].r
sim.tick(1280) # Quarter period
v1 = sim.leds[0].r
assert v1 > v0 # Should increase from bottom of sine
def test_charging_breathing():
"""Charging: LEDs should breathe green smoothly."""
sim = LEDSimulator()
sim.set_state('CHARGING')
# Sample at different points
sim.tick(0)
v0 = sim.leds[0].g
sim.tick(1280) # Quarter period
v1 = sim.leds[0].g
assert v1 > v0 # Should increase
def test_estop_strobe():
"""E-stop: LEDs should strobe red at 8 Hz (125 ms on/off)."""
sim = LEDSimulator()
sim.set_state('ESTOP')
# t=0-124: strobe on
sim.tick(0)
for led in sim.leds:
assert led.r > 0
# t=125-249: strobe off
sim.tick(125)
for led in sim.leds:
assert led.r == 0
def test_pwm_duty_encoding():
"""PWM duty values should encode RGB correctly (GRB, MSB-first)."""
colors = [
RGBColor(255, 0, 0), # Red
RGBColor(0, 255, 0), # Green
RGBColor(0, 0, 255), # Blue
RGBColor(255, 255, 255), # White
]
# Encode to PWM
pwm_buf = rgb_to_pwm_buffer(colors + [RGBColor()] * (NUM_LEDS - 4))
# Verify PWM buffer has correct length
assert len(pwm_buf) == TOTAL_BITS
# Verify bit values are either 0-duty or 1-duty
for pwm in pwm_buf:
assert pwm == BIT_0_DUTY or pwm == BIT_1_DUTY
def test_color_roundtrip():
"""Colors should survive encode/decode roundtrip."""
original = [
RGBColor(100, 150, 200),
RGBColor(0, 255, 0),
RGBColor(255, 0, 0),
] + [RGBColor()] * (NUM_LEDS - 3)
pwm_buf = rgb_to_pwm_buffer(original)
decoded = pwm_buffer_to_rgb(pwm_buf)
for i in range(NUM_LEDS):
assert decoded[i] == original[i]
def test_multiple_state_transitions():
"""Simulate state transitions over time."""
sim = LEDSimulator()
states = ['BOOT', 'ARMED', 'ERROR', 'LOW_BATT', 'CHARGING', 'ESTOP']
for state_name in states:
sim.set_state(state_name)
sim.tick(0)
assert sim.current_state == state_name
if __name__ == '__main__':
pytest.main([__file__, '-v'])