FAQ

Device and Connection

Why is the SLogic32U3 not found?

The most common reason is that the software was launched before the device was connected.

Fix: connect the device first, then launch the host app; or inside the app open Connect to Device → choose the driver → Scan → select the device.

On Linux a normal user has no USB access by default and also needs a udev rule, see below.

Blue only / red only — what's wrong?

• Blue only: USB is not connected as USB3. The cable may not support USB3, a front-panel or incompatible hub is in the way, power is insufficient, or the cable is too long.
• Red only: a Flash load error. Usually a poor cable causing excessive voltage drop, a faulty host USB port, or hardware damage.

In normal operation the indicator should be cyan (blue+green). For the full indicator guide see the Hardware Guide.

Drivers and Permissions

Do I need a driver on Windows?

No. The SLogic32U3 is a WinUSB device by default; Windows 10/11 is plug and play, no Zadig or manual driver install. Just run SLogicView or ngscopeclient after plugging in.

How do I set the Linux udev rule?

The SLogic series USB VID is 359f.

sudo tee /etc/udev/rules.d/60-sipeed.rules <<EOF
SUBSYSTEM!="usb|usb_device", GOTO="sipeed_rules_end"
ACTION!="add", GOTO="sipeed_rules_end"
ATTRS{idVendor}=="359f", MODE="0666", GROUP="plugdev", TAG+="uaccess", ENV{ID_MM_DEVICE_IGNORE}="1"
LABEL="sipeed_rules_end"
EOF
sudo udevadm control --reload
sudo udevadm trigger

On Arch, use GROUP="uucp" instead of GROUP="plugdev". Replug the device once and you can run as a normal user.

Is macOS supported? Any extra setup?

Yes. SLogicView, ngscopeclient and sigrok-cli all provide a macOS build. If the first launch is blocked, allow it under System Settings → Privacy & Security.

Capture and Performance

Why can't the sample rate go higher than a certain value?

The max sample rate depends on the number of channels enabled and the USB bandwidth. Reducing the channel count raises the available rate, but only in fixed groups (4ch=D0–D3, 8ch=D0–D7, 16ch=D0–D15) — arbitrary channels are not supported.

The mapping: 4ch@1400MHz, 8ch@800MHz, 16ch@400MHz, 32ch@200MHz. See Software Guide · Sample rate vs channel count.

Which capture mode does the SLogic32U3 use?

Stream mode: data streams back to the host in real time, with capture length unlimited in theory, bounded only by disk. The onboard 2 Gbit DDR3 acts as an elastic buffer to smooth USB transfer, sustaining 800 MB/s (6.4 Gbps) in practice.

See Software Guide · Stream capture.

What if I get dropped samples?

• Lower the sample rate or reduce the channels enabled.
• Use a USB3 port directly on the motherboard with a good short cable; avoid unpowered hubs and front-panel ports.
• Close other high-traffic USB devices competing for bandwidth.

Decoding

The decode result doesn't match?

Three common causes, in order:

1. Threshold set wrong: match the threshold to the DUT logic level, about 1.6 V for 3.3 V logic.
2. Sample rate too low: take at least 10× the highest signal frequency.
3. Pin mapping wrong: confirm each decoder signal maps to the right channel, e.g. MOSI / MISO / SCLK / CS for SPI.

Empty output only means the current config produced no annotations, not that there is no traffic. Go back to the waveform and confirm the levels are changing.

Firmware and Modes

The device is stuck in DFU mode and won't return to SLogic mode?

Usually the SLogic firmware is corrupted, often from an interrupted OTA. Re-flash the correct firmware with the web update tool to recover.

Can't enter DFU mode, it says "unknown usb device"?

USB enumeration failed, usually from a too-long or poor-quality cable. Use a shorter, better USB cable.

ADC Oscilloscope Module

How do I enable oscilloscope (analog) mode?

Enable it in the ngscopeclient UI. ngscopeclient is now a single binary, with everything configured in the UI and no command-line arguments.

Once enabled, the 32U3 merges D0–7 / D8–15 / D16–23 / D24–31 into 4 analog channels A0–A3 (8-bit); the optional ADC module is required. See ngscopeclient.