High Speed Inter-Chip USB 2.0 Hub and Flash Media Controller

 

 

 

Datasheet

 

Table 6.1 USB4640/USB4640i Pin Descriptions (continued)

 

 

 

 

 

48-PIN

BUFFER

 

 

QFN

TYPE

 

SYMBOL

 

(Table 6.2)

DESCRIPTION

 

 

 

 

PRTCTL[3:2]

7

I/OD6PU

USB Power Enable

 

6

 

As an output, these pins enable power to downstream USB

 

 

 

 

 

 

peripheral devices and have weak internal pull-up resistors. See

 

 

 

Section 6.3, "Port Power Control" for diagram and usage instructions.

 

 

 

As an input, when the power is enabled, these pins monitor the over-

 

 

 

current condition. When an over-current condition is detected, the

 

 

 

pins turn the power off.

 

 

 

 

RBIAS

47

I-R

USB Transceiver Bias

 

 

 

A 12.0 kΩ, ±1.0% resistor is attached from VSS to this pin in order

 

 

 

to set the transceiver's internal bias currents.

 

 

 

 

XTAL1 (CLKIN)

45

ICLKx

24 MHz Crystal Input or External Clock Input

 

 

 

This pin can be connected to one terminal of the crystal or it can be

 

 

 

connected to an external 24 MHz clock when a crystal is not used.

 

 

 

 

XTAL2

44

OCLKx

24 MHz Crystal Output

 

 

 

This is the other terminal of the crystal or it is left open when an

 

 

 

external clock source is used to drive XTAL1(CLKIN).

 

 

 

 

 

 

SECURE DIGITAL INTERFACE

 

 

 

 

SD_D[7:0]

19

I/O8PU

Secure Digital Data 7-0

 

20

 

 

 

23

 

These are the bi-directional data signals SD_D0 - SD_D7 with weak

 

30

 

pull-up resistors.

 

32

 

 

 

33

 

 

 

17

 

 

 

18

 

 

 

 

 

 

SD_CLK

21

O8

Secure Digital Clock

 

 

 

This is an output clock signal to the SD/MMC device.

 

 

 

 

SD_CMD

24

I/O8PU

Secure Digital Command

 

 

 

This is a bi-directional signal that connects to the CMD signal of the

 

 

 

SD/MMC device. The bi-directional signal has a weak internal pull-

 

 

 

up resistor.

 

 

 

 

GPIO15 /

14

I/O6

This general purpose pin may be used either as input, edge sensitive

 

 

 

interrupt input, or output. Custom firmware is required to activate this

 

 

 

function.

 

 

 

 

SD_nCD

 

I/O8PU

Secure Digital Card Detect GPIO

 

 

 

This is a GPIO designated by the default firmware as the Secure

 

 

 

Digital card detection pin and has an internal pull-up.

 

 

 

 

Revision 1.0 (06-01-09)

16

SMSC USB4640/USB4640i

DATASHEET