USB2640I Standard Microsystems Corp., USB2640I Datasheet - Page 17

• Manufacturer Part Number: USB2640I
• Description: Industrial Temperature Usb 2.0 Flash Media Controller And Usb Hub Combo
• Manufacturer: Standard Microsystems Corp.

Industrial Temperature USB 2.0 Flash Media Controller and USB Hub Combo
Chapter 6 Pin Descriptions
SMSC USB2640i/USB2641i
6.1
xD Write Protect
xD Address
Strobe
xD Command
Strobe
xD Data 7-0
xD Read Enable
NAME
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.
USB2640i/USB2641i Pin Descriptions
xD_D[7:0]
SYMBOL
xD_nWP
xD_CLE
xD_nRE
xD_ALE
Table 6.1 USB2640i/USB2641i Pin Descriptions
xD INTERFACE (APPLIES ONLY TO USB2640i)
48-PIN
QFN
21
23
24
30
32
33
13
17
18
19
20
27
DATASHEET
BUFFER
I/O12PD
O12PD
O12PD
O12PD
O12PU
TYPE
17
DESCRIPTION
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.
This pin is an active high Address Latch Enable
signal for the xD device.
This pin has a weak pull-down resistor that is
permanently enabled.
This pin is an active high Command Latch Enable
signal for the xD device.
This pin has a weak pull-down resistor that is
permanently enabled.
These pins are the bi-directional data signal
xD_D7 - xD_D0.
The bi-directional data signal has an internal weak
pull-down resistor.
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).
Revision 2.0 (10-03-08)