NanoBoard 3000 - USB Hub

The NanoBoard 3000 provides a USB 'hub', allowing the connection of up to three USB 2.0-based devices. The three ports are provided courtesy of USB A-type connectors.

Three-port USB hub available for connection of USB-based devices.

The interface between a processor in the FPGA design and the USB devices plugged into the available ports, is handled by an ISP1760 Hi-speed USB Host Controller, from ST-NXP Wireless.

ISP1760 - Hi-speed USB Host Controller device.

This device has a generic processor interface that enables 16- or 32-bit data transfer with the FPGA design's processor, using programmed I/O (PIO) or direct memory access (DMA).
 

 
It has an Enhanced Host Controller Interface (EHCI), a Transaction Translator (TT) and three hi-speed USB transceivers capable of handling high-speed (480Mbps), full-speed (12Mbps) and low-speed (1.5Mbps) transfer modes.

The device supports simultaneous connection of USB devices operating at differing speeds.

Internal clocking for the USB transceivers (and various internal logic) is supplied from an internal PLL, which itself is driven by an external 12MHz crystal connected across the device's XTAL1 and XTAL2 pins.

The device has been set to operate in 'suspend mode' by pulling its SUSPEND-WAKEUP_N pin up to 3.3V. When not in use, all main internal clocks will be stopped to minimize power consumption. The device will 'awaken' (main clocks resume) if an external USB device is connected or disconnected to/from one of the hub ports, or the ISP1760_NCS signal from the FPGA design is asserted (active Low).

Overcurrent detection has been disabled by pulling the respective inputs (OC1_N, OC2_N, OC3_N) up to the VBUS supply.

For each port, the USB data lines (D+, D-) are protected against high transient voltages through the use of a low-capacitance, transient voltage suppressor device – a NUP2201MR6, from ON Semiconductor.

The VBUS lines for the three USB ports are connected to the motherboard's 5V supply via a 5A/15V Multifuse® PPTC resettable fuse (an MF-SM250, from Bourns). This fuse has a hold current of 2.5A, tripping at 5A.

Location on Board

The three external USB hub ports (designated J36, J37, J38) are located along the bottom edge on the solder side of the board. Looking from the front, they can be found to the right of the I/O ports for the SPDIF interface.

USB hub ports (as seen from the front of the board).

The ISP1760 device (designated U61) is located on the component side of the board, to the top-left of the FPGA device used for the Host (NanoTalk) Controller (U30), and below the 1.8" ATA/IDE connector used to attach the satellite TFT LCD panel board (J27).

The 12MHz crystal (designated Y5) is also located on the component side of the board, to the bottom-left of the ISP1760 device.

12MHz crystal.

The three NUP2201MR6 devices (designated U62, U63, U64) are located on the solder side of the board, directly above the external USB hub ports.

NUP2201MR6 voltage suppressor devices.

The resettable fuse (designated F2) is located on the solder side of the board, to the top-left of the audio jacks.

Schematic Reference

The USB Host Controller Interface circuitry can be found on the following sheets of the motherboard schematics:

• Sheet 30 (USB_ISP1760.SchDoc, entitled USB-Host Controller IC)

• Sheet 31 (CON_USBA_RA_UPRIGHT.SchDoc, entitled USBA RA Upright Connector)

Design Interface Component

A variety of design interface components are available from the FPGA NB3000 Port-Plugin.IntLib for access to, and communications with, any or all of the common-bus resources. The design interface component used will depend on which particular resource(s) you wish to access, and how you have configured the Shared Memory Controller – the intermediate design peripheral that sits between a processor in the design and the common-bus resource on the board. For more information, see Accessing Common-Bus Resources on the NanoBoard 3000.

Further Device Information

For more information on the ISP1760 device, refer to the datasheet (ISP1760_4.pdf) available at www.stnwireless.com.

For more information on the NUP2201MR6 device, refer to the datasheet (NUP2201MR6-D.pdf) available at www.onsemi.com.

For more information on the MF-SM250 device, refer to the datasheet (mfsm.pdf) available at www.bourns.com.