SMSC USB2250 Manual De Usuario

Ultra Fast USB 2.0 Multi-Slot Flash Media Controller

SMSC USB2250/50i/51/51i

13

Revision 1.1 (05-29-08)

SM Address 
Strobe

SM_ALE

52

O12PD

This pin is an active high Address Latch 
Enable signal for the SM device.

This pin has a weak pull-down resistor that 
is permanently enabled.

SM Command 
Strobe

SM_CLE

53

O12PD

This pin is an active high Command Latch 
Enable signal for the SM device.

This pin has a weak pull-down resistor that 
is permanently enabled.

SM Data 7-0

SM_D[7:0]

39
40
41
42
43
44
45
46

I/O12PD

These pins are the bi-directional data signals 
SM_D7-SM_D0.

The bi-directional data signal has an internal 
weak pull-down resistor.

SM Read Enable

SM_nRE

55

O12PU

This pin is an active low read strobe signal 
for the SM 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 SM_PU bit of the 
SMC_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).

SM Write Enable

SM_nWE

48

O12PU

This pin is an active low write strobe signal 
for SM 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 SM_PU bit of the 
SMC_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).

SM Write Protect 
Switch

SM_nWPS

38

IPU

A write-protect seal is detected when this pin 
is low. 

This pin has an internal weak pull-up resistor 
that is controlled by the SM_INTF_EN bit of 
the SMC_MODE_CTL2 register.