> For the complete documentation index, see [llms.txt](https://dev.solid-run.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://dev.solid-run.com/solidsense-aiot/solidsense-aiot-tips.md).

# SolidSense AIOT — Tips

Practical notes for the SolidRun SolidSense AIOT carrier: peripherals, how to verify they're up, and how to use them from Linux.

Most of the I²C sensors live on the **Flash Card (J6)** add-on and are enabled by the `*-solidsense-aiot-addon-flash-card` device-tree overlay — apply it (see below) when the card is fitted.

The audio subsystem, by contrast, is on the carrier itself: a TAC5111 codec (I²C2 @ 0x50, U11) with two PDM microphones (U13/U14) and a mono speaker path through a PAM8302 amplifier on connector J5 — see the Audio & Microphone section for record/playback examples.

{% hint style="info" %}
**Find the carrier I²C bus**

```sh
i2cdetect -l        # list adapters
i2cdetect -y 1      # scan it (RZ/V2N carrier = bus 1)
```

In `i2cdetect`: **`UU`** = address claimed by a kernel driver, a **number** = device present but unclaimed, **`--`** = nothing.
{% endhint %}

### Flash Card (J6) Overlay

The J6 add-on sensors (HDC3022, OPT4001, LM3645) live in a device-tree overlay applied at boot only when the card is fitted. On RZ/V2N the flash-card overlay is per-connector (it also wires the camera lane), so pick the one matching where the card is fitted:

| SoM          | Base DTB                           | Flash-Card Overlay                                    |
| ------------ | ---------------------------------- | ----------------------------------------------------- |
| RZ/V2N (J8)  | `r9a09g056n48-solidsense-aiot.dtb` | `rzv2n-solidsense-aiot-addon-flash-card-cam-j8.dtbo`  |
| RZ/V2N (J17) | `r9a09g056n48-solidsense-aiot.dtb` | `rzv2n-solidsense-aiot-addon-flash-card-cam-j17.dtbo` |
| i.MX8MP      | `imx8mp-solidsense-aiot.dtb`       | `imx8mp-solidsense-aiot-addon-flash-card.dtbo`        |

Related CSI camera (IMX678) overlays for RZ/V2N:

* `rzv2n-solidsense-aiot-csi-camera-imx678-j8.dtbo`
* `rzv2n-solidsense-aiot-csi-camera-imx678-j17.dtbo`

***

### Enable via extlinux.conf — updated examples

Copy the `.dtbo` to the boot partition next to the base `.dtb`, then add an `FDTOVERLAYS` line to your boot entry in `/boot/extlinux/extlinux.conf`.

**RZ/V2N (flash card on J8):**

```
LABEL Linux
    KERNEL /Image
    FDT    ../renesas/r9a09g056n48-solidsense-aiot.dtb
    FDTOVERLAYS ../renesas/rzv2n-solidsense-aiot-addon-flash-card-cam-j8.dtbo
    APPEND root=PARTUUID=... rootwait console=ttySC0,115200
```

**i.MX8MP (flash card):**

```
LABEL Linux
    KERNEL /Image
    FDT    ../freescale/imx8mp-solidsense-aiot.dtb
    FDTOVERLAYS ../freescale/imx8mp-solidsense-aiot-addon-flash-card.dtbo
    APPEND root=PARTUUID=... rootwait console=ttymxc1,115200
```

Multiple overlays = space-separated, applied in order (e.g. flash card on J8 plus the IMX678 camera on J17):

```
FDTOVERLAYS /rzv2n-solidsense-aiot-addon-flash-card-cam-j8.dtbo /rzv2n-solidsense-aiot-csi-camera-imx678-j17.dtbo
```

> If U-Boot prints `failed on fdt_overlay_apply … '__symbols__'`, the base dtb wasn't built with `-@` — rebuild it with `make dtbs`.

#### Requirements

* **Base DTB built with symbols (`-@`)** so U-Boot can resolve the overlay's references (`&i2c1`, `&pinctrl`, `&v_3_3`). In-tree this needs `DTC_FLAGS_<base> := -@` **and a full `make dtbs`** — a single `make <vendor>/<board>.dtb` does *not* emit symbols. Verify:

  ```sh
  fdtget <base>.dtb /__symbols__ >/dev/null 2>&1 && echo "has symbols" || echo "rebuild with: make dtbs"
  ```
* **U-Boot with overlay support** (`CONFIG_OF_LIBFDT_OVERLAY=y`), using the extlinux/distro-boot path.

#### Confirm it applied (after boot)

```sh
ls /proc/device-tree/soc/i2c@14400800/   # J6 nodes appear: light-sensor@44, humidity-sensor@46, flash-led@65
i2cdetect -y 1                           # 0x44 / 0x46 / 0x65 now present
```

{% hint style="warning" %}
Without the overlay, none of the J6 sensors show up (the base dtb has no nodes for them). If U-Boot prints `failed on fdt_overlay_apply … '__symbols__'`, the base dtb wasn't built with `-@` — rebuild it with `make dtbs`.
{% endhint %}

### HDC3022 — Temperature & Humidity Sensor

TI **HDC3022** on carrier **I²C1**, address **`0x46`**. Handled by the `hdc3020` IIO driver (`CONFIG_HDC3020`) and read through the **IIO** subsystem — not raw I²C.

#### Verify it is detected

```sh
i2cdetect -y 1
# 40: -- -- -- -- -- -- UU --   <- 0x46 = UU : driver bound

for d in /sys/bus/iio/devices/iio:device*; do echo "$d -> $(cat $d/name)"; done
# /sys/bus/iio/devices/iio:device3 -> hdc3020
```

If `0x46` shows `46` instead of `UU`, the chip is present but the driver didn't bind — check `dmesg | grep hdc3020`. A raw `i2cdump 0x46` of all zeros is normal (command/response chip; always read via IIO).

#### Read temperature and humidity

Values are raw; convert with `value = (raw + offset) × scale` (milli-units, ÷1000 → °C / %RH):

```sh
D=$(grep -l hdc3020 /sys/bus/iio/devices/iio:device*/name | xargs dirname)

awk -v tr=$(cat $D/in_temp_raw) -v ts=$(cat $D/in_temp_scale) -v to=$(cat $D/in_temp_offset) \
    -v hr=$(cat $D/in_humidityrelative_raw) -v hs=$(cat $D/in_humidityrelative_scale) \
    'BEGIN{ printf "Temperature: %.2f C\nHumidity:    %.2f %%RH\n", (tr+to)*ts/1000, hr*hs/1000 }'
# Temperature: 26.10 C
# Humidity:    50.76 %RH
```

#### Continuous read loop

```sh
D=$(grep -l hdc3020 /sys/bus/iio/devices/iio:device*/name | xargs dirname)
while true; do
  awk -v tr=$(cat $D/in_temp_raw) -v ts=$(cat $D/in_temp_scale) -v to=$(cat $D/in_temp_offset) \
      -v hr=$(cat $D/in_humidityrelative_raw) -v hs=$(cat $D/in_humidityrelative_scale) \
      'BEGIN{ printf "%.2f C   %.2f %%RH\n", (tr+to)*ts/1000, hr*hs/1000 }'
  sleep 1
done
```

Breathe on the sensor — humidity jumps, temperature drifts up, then both settle. `in_*_peak_raw` hold the max since power-on; `iio_info` (libiio) dumps everything with units.

### OPT4001 — Ambient Light Sensor

TI **OPT4001** on carrier **I²C1**, address **`0x44`**. Driver `opt4001` (`CONFIG_OPT4001`). The device-tree `compatible` **must match the package**: `ti,opt4001-sot-5x3` (SOT-5X3) or `ti,opt4001-picostar` (PicoStar).

#### Verify it is detected

```sh
i2cdetect -y 1                       # 0x44 = UU
for d in /sys/bus/iio/devices/iio:device*; do echo "$d -> $(cat $d/name)"; done
# ... -> opt4001
```

#### Read illuminance

The driver reports **processed lux** directly:

```sh
D=$(grep -l opt4001 /sys/bus/iio/devices/iio:device*/name | xargs dirname)
cat $D/in_illuminance_input          # lux           e.g. 203.167562500
cat $D/integration_time              # current integration time (s)
cat $D/integration_time_available    # selectable values (s)
```

**Example on RZ/V2N:**

```shell
root@rzv2n-sr-som:~# D=$(grep -l opt4001 /sys/bus/iio/devices/iio:device*/name | xargs dirname)
root@rzv2n-sr-som:~# echo $D
/sys/bus/iio/devices/iio:device3
root@rzv2n-sr-som:~# cat $D/in_illuminance_input
211.546125000
root@rzv2n-sr-som:~# cat $D/integration_time_available
0.000600 0.001000 0.001800 0.003400 0.006500 0.012700 0.025000 0.050000 0.100000 0.200000 0.400000 0.800000
```

Read loop:

```sh
D=$(grep -l opt4001 /sys/bus/iio/devices/iio:device*/name | xargs dirname)
while true; do echo "$(cat $D/in_illuminance_input) lux"; sleep 1; done
```

Cover the sensor → lux drops toward 0; shine a light → it rises.

{% hint style="warning" %}
**Not detected (`0x44` absent)?** The chip isn't ACKing. Confirm it's populated on the card, then check the **SDA/VDD solder joints** — with power off, verify continuity from the OPT4001 SDA pin to a known-good bus SDA point (e.g. the HDC3022 SDA). An open/cold joint (SDA floating near 0 V while the bus works for other devices) is a board/assembly fault, not software.
{% endhint %}

### LM3645 — Camera Flash LED

TI **LM3645** flash/torch LED driver on carrier **I²C1**, address **`0x65`**.

#### Verify it is detected

```sh
i2cdetect -y 1
# 60: -- -- -- -- -- 65 --        <- 0x65 present (a number, not UU: no kernel driver)

# read a register to confirm it responds (-f since no driver claims it):
i2cget -y -f 1 0x65 0x00
```

The Flash Card (J6) carries a **TI LM3645** flash driver powering **4× SFH4722 IR emitters**. It is exposed through the Linux **LED flash class** at:

```
/sys/class/leds/ir:flash
```

#### Prerequisites

* Flash Card fitted on connector **J6**.
* Flash Card device-tree overlay applied: `rzv2n-solidsense-aiot-addon-flash-card-cam-j8.dtbo` (or `…-j17.dtbo` for J17; `imx8mp-solidsense-aiot-addon-flash-card.dtbo` on i.MX8MP).
* Driver loaded (`leds-lm3645`).

Verify the device is present and bound:

```sh
lsmod | grep lm3645              # leds_lm3645 loaded
i2cdetect -y 1                   # 'UU' at 0x65 = driver bound
ls /sys/class/leds/              # shows: ir:flash
```

{% hint style="info" %}
If the module is built as a module and not auto-loaded, run `modprobe leds-lm3645`.
{% endhint %}

#### Torch — continuous IR

```sh
cd /sys/class/leds/ir:flash
cat max_brightness        # torch steps available (e.g. 255)
echo 128 > brightness     # IR torch ON (mid level)
echo 0   > brightness     # OFF
```

#### Flash — pulsed IR

```sh
cd /sys/class/leds/ir:flash
cat max_flash_brightness          # max flash current (µA)
echo 1000000 > flash_brightness   # 1 A per output (µA)
echo 100000  > flash_timeout      # 100 ms pulse (µs)
echo 1       > flash_strobe       # fire one pulse (auto-clears)
```

#### Current & timing reference (per output)

| Mode    | Formula                         | Range             |
| ------- | ------------------------------- | ----------------- |
| Flash   | `I = 7.8 mA × code + 7.325 mA`  | \~7 mA … 2 A      |
| Torch   | `I ≈ 1.4 mA × level + 0.525 mA` | \~0.5 mA … 360 mA |
| Timeout | tabulated                       | 10 ms … 400 ms    |

All four outputs are driven identically, so total emission ≈ **4×** the per-output current. Written values are clamped to the device-tree limits (`flash-max-microamp`, `led-max-microamp`, `flash-max-timeout-us`).

#### Confirming it works

{% hint style="info" %}
IR light is **invisible to the eye**. Point a **phone or USB camera** at the four emitters while running torch/flash — IR appears as a faint **violet-white glow** on the camera sensor. Phone *front* cameras usually lack an IR-cut filter and show it best.
{% endhint %}

#### Notes

* Strobe is **software/I2C** triggered; the hardware STR1/STR2 pins are not used.
* HWEN is handled automatically by the driver (`enable-gpios`, pin **P72**).
* Camera-synchronized IR (V4L2 flash) is not wired in this driver version.

{% hint style="danger" %}
**Eye safety:** IR is invisible but can be intense at high current. Do not stare into the emitters, and keep the flash/torch current within the rated limit.
{% endhint %}

### LTE SIM Card Detection (GC02S1) — Polling-Mode

The SolidSense AIOT uses the Sequans **GC02S1** LTE modem with **SIM detection in polling mode**: the modem detects the USIM electrically, polling at a fixed interval, **without** using the SIM card-detect (CD) signal. This is the standard SIM configuration for the board.

{% hint style="success" %}
**This is the default on production units.** SolidRun provisions the GC02S1 with SIM polling mode during manufacturing, so boards ship with this as the default SIM-detection mode (no card-detect line required). The steps below are only needed to (re)apply it on a module that isn't already configured.
{% endhint %}

#### Configuration

To set the modem to SIM polling mode, send these AT commands in order:

```
AT+CFUN=5
AT+SQNHWCFG="sim0","enable","10000"
AT^RESET
AT+CFUN=5
AT+SQNFACTORYSAVE="OEM"
```

* `AT+CFUN=5` — enter manufacturing mode (required to change hardware config).
* `AT+SQNHWCFG="sim0","enable","10000"` — enable SIM polling; the 3rd parameter is the **poll interval in milliseconds** (10000 = 10 s).
* `AT^RESET` — reboot the modem to apply.
* `AT+SQNFACTORYSAVE="OEM"` — store the setting as the module default.

#### Applying from Linux

The modem's AT port enumerates as `/dev/ttyACM0`. Open it, start a background reader, then send each command with `printf`:

```sh
# open the AT port and read responses
PORT=/dev/ttyACM0
stty -F $PORT 115200 raw -echo -onlcr
cat $PORT & CATPID=$!

# enable SIM polling mode
cmd='AT+CFUN=5'                          ; printf '%s\r' "$cmd" > $PORT ; sleep 1
cmd='AT+SQNHWCFG="sim0","enable","10000"'; printf '%s\r' "$cmd" > $PORT ; sleep 1
cmd='AT^RESET'                           ; printf '%s\r' "$cmd" > $PORT ; sleep 20
```

`AT^RESET` re-enumerates the modem over USB, so re-open the port before persisting and verifying:

```sh
# re-open the port after the modem reboots
ls /dev/ttyACM*
PORT=/dev/ttyACM0
stty -F $PORT 115200 raw -echo -onlcr
cat $PORT & CATPID=$!

# persist the setting as the module default
cmd='AT+CFUN=5'                ; printf '%s\r' "$cmd" > $PORT ; sleep 1
cmd='AT+SQNFACTORYSAVE="OEM"'  ; printf '%s\r' "$cmd" > $PORT ; sleep 1
```

#### Verify

Allow \~10 s after boot (one poll interval), then:

```sh
cmd='AT+CPIN?'    ; printf '%s\r' "$cmd" > $PORT ; sleep 1   # -> +CPIN: READY
cmd='AT+SQNCCID?' ; printf '%s\r' "$cmd" > $PORT ; sleep 1   # -> valid ICCID
cmd='AT+CIMI'     ; printf '%s\r' "$cmd" > $PORT ; sleep 1   # -> valid IMSI
```

A `+CPIN: READY` response with a valid ICCID and IMSI confirms the SIM is detected and working.

{% hint style="info" %}
**One-time setting.** `AT+SQNHWCFG` is stored in non-volatile memory and `AT+SQNFACTORYSAVE="OEM"` makes it the module default, so it **persists across reset and power-cycle**. Apply it once per modem; it does not need to be re-run at each boot.
{% endhint %}

### Audio & Microphone

The SolidSense AIOT carries a **Texas Instruments TAC5111IRGER** audio codec (**U11**, on **I²C2 address 0x50**) that provides both a stereo PDM microphone input and a mono speaker output path.

**Hardware**

| Function    | Part                     | Designator | Notes                                                                 |
| ----------- | ------------------------ | ---------- | --------------------------------------------------------------------- |
| Audio codec | TAC5111IRGER             | U11        | I²C2 @ 0x50, I²S on SAI3, **S16\_LE only**                            |
| Microphones | MMICT5837-00-012 ×2      | U13, U14   | PDM digital mics → codec IN1 / IN2                                    |
| Speaker amp | PAM8302AASCR             | —          | Single-channel class-D, driven from codec **OUT1**; **OUT2 grounded** |
| Speaker out | J5 (2×1, 1.27 mm header) | J5         | Amplifier output                                                      |

The codec's **OUT1** feeds the PAM8302 amplifier; **OUT2 is grounded** and unused. Because the PAM8302 is a single-ended-input amp wired with OUT1M as the reference, the OUT1 channel must be driven in **pseudo-differential mode with OUTxM as VCOM** — plain differential mode produces loud noise. The amplifier `/SD` (shutdown) enable is on **GPIO1\_IO12** (active-high) and must be asserted before playback.

> ⚠️ Only **S16\_LE** is supported (S32\_LE is buggy in the driver).

#### Recording (microphone)

The two MMICT5837 PDM mics map to codec channels IN1/IN2. Set the input mux to PDM, enable the two ASI capture channels, set a sane PDM gain and clock, then record:

```sh
# Route both mics through the PDM input path
amixer -c 0 sset 'IN1 Source Mux' 'PDM'
amixer -c 0 sset 'IN2 Source Mux' 'PDM'

# Enable both capture channels on the audio serial interface
amixer sset 'ASI_TX_CH1_EN' cap
amixer sset 'ASI_TX_CH2_EN' cap

# PDM digital gain — try 160–200 (NOT 255); raise until just below clipping
amixer sset 'PDM1 Digital' 180

# PDM clock — 1.4112 MHz or 1.536 MHz
amixer sset 'PDM Clk Divider' '1.4112 MHz'

# Record 60 s, stereo, 48 kHz, 16-bit
arecord -D hw:0,0 -c 2 -r 48000 -f S16_LE -d 60 rec.wav

# Trim the first 0.5 s of startup noise
sox rec.wav rec_trim.wav trim 0.5
```

#### Playback (speaker)

Enable the DAC receive channel and route OUT1 through the DAC into the amplifier using the VCOM pseudo-differential configuration:

```sh
amixer -c 0 sset 'ASI_RX_CH1_EN' on
amixer -c 0 sset 'OUT1x Source' 'DAC Input'
amixer -c 0 sset 'OUT1x Config' 'Pseudo differential with OUTxM as VCOM'
amixer -c 0 sset 'OUT1x Driver' 'Line-out'

aplay -D hw:0,0 rec_trim.wav
```


---

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