USB2244 Standard Microsystems Corp., USB2244 Datasheet - Page 10

• Manufacturer Part Number: USB2244
• Description: Usb2244/usb2244i Ultra Fast Usb 2.0 Sd/mmc Flash Media Controller
• Manufacturer: Standard Microsystems Corp.

Chapter 5 Pin Descriptions
Revision 1.0 (05-27-08)
5.1
SD Data
SD Clock
SD Command
SD Write Protect
SD Card Detect
GPIO
USB Bus Data
USB Transceiver
Bias
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 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” signals. 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.
Pin Descriptions
SD_D[7:0]
SD_CLK
SD_CMD
SD_nWP
GPIO15
(SD_nCD)
USB+
USB-
RBIAS
SYMBOL
Table 5.2 USB2244/2244i 36-Pin QFN Pin Descriptions
SECURE DIGITAL INTERFACE
36-PIN
QFN
10
20
23
25
30
26
35
11
7
8
4
5
9
2
3
USB INTERFACE
DATASHEET
I/O12PU
O12
I/O12PU
I/O12
I/O12
I/O-U
I-R
BUFFER
TYPE
10
The bi-directional signals should have weak
pull-up resistors. The register can be
controlled by: SD_MMC_INTF_EN bit of
SDC_MODE_CTL
This is an output clock signal to SD/MMC
device.
The clock frequency is software configurable.
This is a bi-directional signal that connects to
the CMD signal of SD/MMC device. The bi-
directional signal should have an internal weak
pull-up resistor.
The pull-up register can be controlled by:
SD_MMC_INTF_EN bit of SDC_MODE CTL
This pin is designated as the Secure Digital
card mechanical write detect pin.
This is a GPIO designated as the Secure
Digital card detection pin.
These pins connect to the USB bus data
signals.
A 12.0k , 1.0% resistor is attached from VSSA
to this pin in order to set the transceiver's
internal bias currents.
Ultra Fast USB 2.0 SD/MMC Flash Media Controller
DESCRIPTION
SMSC USB2244/USB2244i
Datasheet