SMSC USB2640, USB2640i Chapter 6 Pin Descriptions, 6.1USB2640/USB2641 Pin Descriptions, QFN, NAME, TYPE, 48-PIN, BUFFER, SYMBOL, DESCRIPTION, xD INTERFACE (APPLIES ONLY TO USB2640)

Ultra Fast USB 2.0 Multi-Format Flash Media Controller/USB Hub Combo

Chapter 6 Pin Descriptions

This section provides a detailed description of each signal. The signals are arranged in functional groups according to their associated interface.

The “n” symbol in the signal name indicates that the active, or asserted, state occurs when the signal is at a low voltage level. When “n” is not present before the signal name, the signal is asserted when at the high voltage level.

The terms assertion and negation are used exclusively. This is done to avoid confusion when working with a mixture of “active low” and “active high” signal. The term assert, or assertion, indicates that a signal is active, independent of whether that level is represented by a high or low voltage. The term negate, or negation, indicates that a signal is inactive.

6.1USB2640/USB2641 Pin Descriptions

Table 6.1 USB2640/USB2641 Pin Descriptions

		48-PIN	BUFFER
NAME	SYMBOL	QFN	TYPE	DESCRIPTION
	xD INTERFACE (APPLIES ONLY TO USB2640)
xD Write Protect	xD_nWP	21	O12PD	This pin is an active low write protect signal for the
				xD device.
				This pin has a weak pull-down resistor that is
				permanently enabled.
xD Address	xD_ALE	23	O12PD	This pin is an active high Address Latch Enable
Strobe				signal for the xD device.
				This pin has a weak pull-down resistor that is
				permanently enabled.
xD Command	xD_CLE	24	O12PD	This pin is an active high Command Latch Enable
Strobe				signal for the xD device.
				This pin has a weak pull-down resistor that is
				permanently enabled.
xD Data 7-0	xD_D[7:0]	30	I/O12PD	These pins are the bi-directional data signal
		32		xD_D7 - xD_D0.
		33		The bi-directional data signal has an internal weak
		13
				pull-down resistor.
		17
		18
		19
		20
xD Read Enable	xD_nRE	27	O12PU	This pin is an active low read strobe signal for the
				xD device.
				When using the internal FET, this pin has an
				internal weak pull-up resistor that is tied to the
				output of the internal Power FET and is controlled
				by the xD_PU bit of the xDC_CTL register.
				If an external FET is used (Internal FET is
				disabled), then the internal pull-up is not available
				(external pull-ups must be used).

SMSC USB2640/USB2641	17	Revision 2.0 (10-03-08)
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