Day41 - IIO Control Plane v3 Integration¶

🧪 Lab Objective¶

Validate end-to-end behavior between:

STM32 sensor firmware
Linux IIO driver

Focus:

Mode control
One-shot trigger
Data consistency

🔧 Setup¶

Ensure:

Driver loaded
Device present:

ls /sys/bus/iio/devices/

Example:

iio:device0

🧪 Lab 1 – One-Shot Mode Behavior¶

Step 1: Set mode¶

echo one-shot | sudo tee /sys/bus/iio/devices/iio:device0/mode

Step 2: Read data without trigger¶

cat /sys/bus/iio/devices/iio:device0/in_voltage0_raw
cat /sys/bus/iio/devices/iio:device0/in_voltage0_raw

Expected:

101
101

✔ No automatic sampling ✔ Mode is passive

🧪 Lab 2 – Trigger One-Shot¶

Step 1: Trigger¶

echo 1 | sudo tee /sys/bus/iio/devices/iio:device0/one_shot

Step 2: Read result¶

cat /sys/bus/iio/devices/iio:device0/in_voltage0_raw

Expected:

Step 3: Read again¶

cat /sys/bus/iio/devices/iio:device0/in_voltage0_raw

Expected:

✔ Single update ✔ Value remains stable

🧪 Lab 3 – Multiple One-Shot Triggers¶

echo 1 | sudo tee /sys/bus/iio/devices/iio:device0/one_shot
cat /sys/bus/iio/devices/iio:device0/in_voltage0_raw

echo 1 | sudo tee /sys/bus/iio/devices/iio:device0/one_shot
cat /sys/bus/iio/devices/iio:device0/in_voltage0_raw

Expected:

103
104

✔ Each trigger generates new sample

🧪 Lab 4 – Invalid Mode Usage¶

echo continuous | sudo tee /sys/bus/iio/devices/iio:device0/mode
echo 1 | sudo tee /sys/bus/iio/devices/iio:device0/one_shot

Expected:

Operation rejected
Error returned

✔ Driver enforces mode constraint

🧪 Lab 5 – Buffer Protection¶

(If buffer enabled)

echo 1 > buffer/enable
echo 1 > one_shot

Expected:

-EBUSY or failure

✔ Prevents conflicting operations

📊 Behavior Summary¶

Action	Result
Set mode = one-shot	No sampling
Trigger	One sample generated
Read raw	Latest value
Re-read	Same value
Re-trigger	New sample

🧠 Lab Conclusion¶

The system behaves as:

Deterministic
Explicitly controlled
Fully decoupled

This confirms:

Control plane design is correct
Linux ↔ firmware integration is stable