SolidSense AIOT — Tips

Practical tips for the SolidRun SolidSense AIOT carrier — Flash Card (J6) overlay + I²C sensors (HDC3022, OPT4001) and on-board audio (TAC5111 codec, PDM mics, PAM8302 speaker).

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.

Find the carrier I²C bus

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.

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:

  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)

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

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.

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

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):

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

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

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:

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:

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:

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.

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.

LM3645 — Camera Flash LED

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

Verify it is detected

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:

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

If the module is built as a module and not auto-loaded, run modprobe leds-lm3645.

Torch — continuous IR

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

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

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.

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.

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.

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.

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.

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:

# 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:

# 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:

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.

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.

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:

# 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:

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