USB 2.0 Embedded Host testing
The USB 2.0 Embedded Host is covered in the On-The-Go and Embedded Host supplement of the USB 2.0 Spec. An Embedded host is defined as a non-PC hosts that supports a specific, targeted set of peripherals. The developer of each Targeted Host product defines the set of supported peripherals on a Targeted Peripheral List (TPL). It has one or more Standard-A or Micro-AB receptacles. Embedded Host products may also offer USB peripheral capability, delivered separately via one or more Type-B receptacles (device). In addition it is possible for an Embedded Host to be a Charging Downstream Port (CDP) as defined in the Battery Charging Specification 1.2.
For the USB-IF Compliance program an Embedded Host should under go the following test:
- High Speed Electrical
- Full/Low Speed Signal Quality
- Vbus Drop
- Vbus Droop
- TPL Functionality Interoperability Test
- Battery Charging 1.2 Capabilities
| USB 2.0 Embedded Host | High Speed Electrical | Full Speed Signal Quality | Low Speed Signal Quality | Vbus Drop | Vbus Droop | Interoperability Manual Testing | Battery Charging tests (CDP) |
High
Speed  |
Y | Y | F | Y | M | Y | F |
Full
Speed  |
Y | F | Y | M | Y | F | |
| Low
Speed |
Y | Y | M | Y | F |
Y = Always required
F = Required if feature is supported
M = Required if there are multiple downstream ports
If the product support Battery
Charging 1.2 the product must under go the Battery Charging 1.2
compliance tests
When submitting for USB-IF Compliance also take care of the following:
- Check that the product complies with the USB-IF requirements
of the USB-IF Compliance website
- Complete the VIF file. You can download the USB Vendor Info
File Generator at www.usb.org
- Make sure that the used A or micro-AB Receptacle is USB-IF certified
!!!
- Carefully read Chapter 7 of the USB
On-The-Go and Embedded Host Automated Compliance Plan 1.2 and
go through all the manual
test.
- Make sure that a High Speed capable embedded host must
be able to enter the high
speed electrical test modes via PID/VID
detection.
When completing the Checklist and TPL take the following into account:
- TPL must be detailed enough for example for storage:
- Define in detail what type is supported like USB DVD/CDROM, Floppy, Pendrive, Harddrive, Flashcard reader, how many partions are supported, what file systems (FAT32, NTFS,...), are additional interfaces supported.
- Make sure it's future prove there UASP is starting to come for storage.
- Include at least one device that prove to work with it's details
- Know the suspend/resume behavoir of the embedded host.
- USB Suspend state is when Vbus is still 5V and D+ high and D- low and the connected device is in suspend state.
- Take remote wakeup into acount if TPL include remote wakeup devices.
- Include all different type of suspend that are
supported.
- Overcurrent test
- Intens Interoperability with many different devices
- TDR Impedance measurement
- Real time EYE diagram
- Testing under different temperatures conditions
- Test the Checklist items that are not coverd in the compliance plan
- High Speed disconnect detect test