SMSC USB2244i Manual De Usuario

Ultra Fast USB 2.0 SD/MMC Flash Media Controller

SMSC USB2244/USB2244i

11

Revision 1.0 (05-27-08)

24MHz Crystal 
or external clock 
input

XTAL1 
(CLKIN)

33

ICLKx

This pin can be connected to one terminal of 
the crystal or it can be connected to an external 
24 clock when a crystal is not used.

24MHz  Crystal

XTAL2

32

OCLKx

This is the other terminal of the crystal, or it can 
be left open when an external clock source is 
used to drive XTAL1(CLKIN).  It may not be 
used to drive any external circuitry other than 
the crystal circuit.

3.3V Analog 
Power 

VDDA33

36

3.3V Analog Power 

1.8V PLL Power 

VDD18PLL

34

This pin is the 1.8V Power for the PLL.

+1.8V Filtered analog power for internal PLL. 
This pin must have a 1.0

μ

F(or greater) ±20% 

(ESR <0.1

Ω) capacitor to VSS.

General Purpose 
I/O

GPIO1 (LED1)

1

I/O12

This pin may be used either as input, edge 
sensitive interrupt input, or output.

In addition, as an output, the GPIO1 can use 
output controlled by the LED1_GPIO1 register.

General Purpose 
I/O

GPIO2 / RXD / 
SDA

27

I/O12

GPIO: This pin may be used either as input, 
edge sensitive interrupt input, or output.

I

RXD: In addition to the above, the signal can 
be used as input to the RXD of UART in the 
device, when the TXD_RXD_SEL bit in 
UTIL_CONFIG1 register is cleared to "0".

I/O12

SDA: This is the data pin when used with an 
external serial EEPROM.

General Purpose 
I/O

GPIO4

29

I/O12

This pin may be used either as input, edge 
sensitive interrupt input, or output. 

General Purpose 
I/O

GPIO7 / 
TXD / 
SCK 

31

I/O12

GPIO: This pin may be used either as input, 
edge sensitive interrupt input, or output.

O12

TXD: In addition, as an output, the GPIO7 can 
be used as an output TXD of UART in the 
device, when the GPIO2/TXD bit in 
UTL_CONFIG register is set to "1"

O12

SCK: This is the clock output when used with 
an external EEPROM. 

General Purpose 
I/O

GPIO10 
(CRD_PWR)

21

I/O200

GPIO: This pin may be used either as input, 
edge sensitive interrupt input, or output. 

CRD_PWR: Card Power drive of 3.3V @ either 
100mA or 200mA.

General Purpose 
I/O

GPIO14

19

I/O12

This pin may be used either as input, edge 
sensitive interrupt input, or output. 

RESET Input

nRESET

18

IS

This active low signal is used by the system to 
reset the chip. The active low pulse should be 
at least 1

μs wide.