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dsap Diagnostic Cable Instructions

Purpose

Use this Windows-only guide to connect the diagnostic cable to a running device and open a read-only serial-monitoring session. This guide ends when the terminal connection is open. It does not describe device settings, status messages, or diagnostic procedures.

Prerequisites

Before starting, have the following available:

  1. A completed diagnostic cable.
  2. A Windows laptop with an available USB-A port and internet access.
  3. The device to observe.
  4. Either Tera Term or PuTTY installed on the Windows laptop.

The cable uses a Silicon Labs CP210x USB-to-UART bridge. Install the CP210x VCP driver for Windows before connecting the cable. Follow the installer or driver package instructions supplied by Silicon Labs.

For cable background and specifications, see the Adafruit USB-to-TTL serial cable.

1. Verify the Cable Assembly

Diagnostic cable showing the 5 V, ground, serial-data, and unused leads

The cable is a read-only serial monitor. Verify that its leads match the annotated photo:

Lead Connection and use
Red 5 V charging power. Leave it connected to charge the device. Disconnect it before connecting the cable when observing a device without charging it.
Black Ground. Leave it connected.
White Device TX to PC. Leave it connected to observe device activity.
Green Unused. Leave it disconnected.

2. Connect the Cable and Find Its COM Port

2.1 Confirm USB-C Orientation

When plugging the cable into the device, make sure the orientation of the USB-C board matches the photos below.

USB-C breakout board connected to an open device with its PCBs exposed
Open device with exposed PCBs
USB-C breakout board connected to an assembled device in its case
Assembled device in its case

2.2 Connect the Cable and Find Its COM Port

  1. If you want to observe the device without charging it, disconnect the red 5 V lead first. Otherwise, leave the lead connected.
  2. Insert the diagnostic cable's USB-C connector into the device.
  3. Connect the USB-A connector to the Windows laptop.
  4. Open Device Manager, then expand Ports (COM & LPT).
  5. Find the entry for the Silicon Labs CP210x USB-to-UART bridge and record its COM port number, such as COM7.

If the CP210x entry does not appear, disconnect the cable, confirm the driver installation completed, reconnect the cable, and check Device Manager again.

3. Open the Serial Connection

Use one of the following terminal applications. In either application, select the COM port found in Device Manager and use these settings:

Setting Value
Speed 57600 baud
Data bits 8
Parity None
Stop bits 1
Flow control None

Option A: Tera Term

  1. Download and install Tera Term from the official Tera Term release page.
  2. Start Tera Term. In the New connection dialog, select Serial and choose the recorded COM port.
  3. Select Setup > Serial port.
  4. Set the speed to 57600 and confirm the remaining values match the serial settings table above.
  5. Select OK to open the serial-monitoring session.

Option B: PuTTY

  1. Download and install PuTTY from the official PuTTY download page.
  2. Start PuTTY and select Serial as the connection type.
  3. Enter the recorded COM port in Serial line and enter 57600 in Speed.
  4. Select Connection > Serial. Confirm that data bits are 8, stop bits are 1, parity is None, and flow control is None.
  5. Return to Session and select Open to open the serial-monitoring session.

The serial connection is now initialized. Continue with any applicable Sonogen diagnostic procedures.