Purpose

Process two pedal sensors and output a safe, normalized throttle value.

• Converts raw ADC → pedal % (0–1)
• Ensures both sensors agree
• Detects faults (electrical + plausibility)
• Prevents brake + throttle simultaneously

High Level Flow

Raw ADC → Filter → % Mapping → Voltage Check → Faults → Output

Update Function

APPS_UpdateData(raw1, raw2)

1. Filter Inputs

• Apply low-pass filter (100 Hz)
• Smooths noise and spikes
• This helps keep the pedal signal stable instead of jumping around from tiny electrical fluctuations

2. Convert to Pedal %

• Uses calibrated raw values:

rest → 0%
full → 100%

apps1 = LINEAR_MAP(raw1, REST1, FULL1, 0 → 1)
apps2 = LINEAR_MAP(raw2, REST2, FULL2, 0 → 1)

• This means the code is mainly built around real measured ADC values from the pedal, not just ideal voltages
• That makes calibration easier because the mapping matches the actual installed hardware

3. Clamp Values

• Ensure:

0 ≤ APPS ≤ 1

• If the sensor goes slightly below rest or above full travel, the final output is still kept in a safe range

4. Convert to Voltage Used for fault detection only:

voltage = ADC_VALUE_TO_VOLTAGE(raw)

• The code still converts raw readings into voltage so it can check for open-circuit or short-circuit behavior
• So percentage is based mainly on raw ADC calibration, while voltage is used mainly for electrical safety checks

5. Voltage Safety Check

APPS1 (3.3V):

0.33V → 2.97V (fault range)

APPS2 (5V):

0.5V → 4.5V (fault range)

• If a sensor voltage goes outside these ranges for too long, the system raises an APPS fault
• This helps catch wiring issues, sensor faults, or readings that are no longer physically believable

6. Sensor Agreement Check

difference = |APPS1 - APPS2|

If:

difference > 0.1 (10%)

→ FAULT

• Since the pedal uses two sensors, they should track each other closely
• If they disagree too much, the system treats that as unsafe

7. Brake Plausibility Check

If:

Throttle > 25%
AND
Brake > threshold

→ FAULT

Reset when:

Throttle < 5%

• This prevents the car from accepting heavy throttle while strong braking is also being detected

Output

APPS = (APPS1 + APPS2) / 2

• The final pedal command is the average of both sensors
• This gives one clean throttle value to pass into the rest of the vehicle logic

ADS1115 Integration

The APPS code is fed by the ADS1115 external ADC.

In adc.cpp, the ADS reads the two pedal channels and passes them into:

APPS_UpdateData(raw1, raw2);

So the flow is:

Pedal sensor → ADS1115 → raw ADC counts → APPS_UpdateData()

Why use the ADS1115?

The ADS1115 gives 16-bit readings, which means it can measure the sensor signal with much finer resolution than a typical 12-bit onboard ADC.

That helps because:

• higher resolution gives smaller voltage steps between readings
• better precision makes pedal calibration cleaner
• less quantization error means smoother percentage mapping
• less noise sensitivity makes the signal easier to filter and trust

In simple terms, the ADS gives the APPS module a more detailed picture of what the pedal is doing.

Why that matters for APPS

Since APPS is safety-critical, better signal quality is valuable:

• small pedal changes are easier to detect
• the filtered signal is smoother
• the two sensors can be compared more accurately
• fault checks become more reliable

So while the APPS logic itself is mainly based on filtered raw counts and calibration, the ADS1115 improves the quality of those raw counts before APPS ever sees them.

Summary

APPS:

• Converts pedal → throttle
• Verifies sensor agreement
• Blocks unsafe conditions

The ADS1115 helps by giving high-resolution 16-bit sensor readings with better accuracy and lower effective noise, making the APPS signal cleaner and more trustworthy before torque is commanded.