SMSC USB2640i - Manual (Page 27)

Ultra Fast USB 2.0 Multi-Format Flash Media Controller/USB Hub Combo
SMSC USB2640/USB2641 27 Revision 2.0 (10-03-08)
DATASHEET
Chapter 7 Configuration Options
7.1 Hub
SMSC’s USB 2.0 hub is fully compliant to the Universal Serial Bus Specification available from the
USB Implementer’s Forum found at http://www.usb.org (Revision 2.0 April 27, 2000 and the 12/7/2000
and 5/28/2002 Errata) . Please reference Chapter 11 (Hub Specification) for general details regarding
hub operation and functionality.
The hub provides 1 transaction translator (TT) that is shared by both downstream ports (defined as
single-TT configuration). The TT contains 4 non-periodic buffers.
7.1.1 Hub Configuration Options
The SMSC hub supports a large number of features (some are mutually exclusive), and must be
configured in order to correctly function when attached to a USB host controller. There are two principal
ways to configure the hub; The internal default settings or by settings stored in an external EEPROM
or SPI Flash device.
7.1.1.1 Power Switching Polarity
The hub only supports “active high” port power controllers.
7.1.2 VBus Detect
According to Section 7.2.1 of the USB 2.0 Specification, a downstream port can never provide power
to its D+ or D- pull-up resistors unless the upstream port’s VBUS is in the asserted (powered) state.
The VBUS_DET pin on the hub monitors the state of the upstream VBUS signal and will not pull-up
the D+ resistor if VBUS is not active. If VBUS goes from an active to an inactive state (Not Powered),
the hub will remove power from the D+ pull-up resistor within 10 seconds.
7.2 Card Reader
The SMSC USB2640/USB2641 is fully compliant with the following flash media card reader
specifications:
„
Memory Stick Specification 1.43
„
Memory Stick Pro Format Specification 1.02
„
Memory Stick Pro-HG Duo Format Specification 1.01
-Memory Stick, MS Duo, HS-MS, MS Pro-HG, MS Pro
„
xD-Picture Card 1.2 compliant
„
Secure Digital 2.0 / MultiMediaCard Specification 4.3
-SD 2.0, HS-SD, HC-SD
-TransFlash™ and reduced form factor media
-1/4/8 bit MMC 4.2
7.3 System Configurations
7.3.1 EEPROM/SPI Interface
The USB2640/USB2641 can be configured via a 2-wire (I 2 C) EEPROM (256x8) or an external SPI
flash device containing the firmware for the USB2640/USB2641. If an external configuration device
does not exist the internal default values will be used. If one of the external devices is used for