SMSC LAN9311 User Manual

Two Port 10/100 Managed Ethernet Switch with 16-Bit Non-PCI CPU Interface

SMSC LAN9311/LAN9311i

33

Revision 1.4 (08-19-08)

 

Note: For more information on configuration straps, refer to 

. Additional strap pins, which share functionality with the EEPROM pins, are described

in 

Configuration strap values are latched on power-on reset or nRST de-assertion.
Configuration strap pins are identified by an underlined symbol name. Some configuration
straps can be overridden by values from the EEPROM Loader. Refer to 

 for more information.

69

Port 1 Auto-

MDIX Enable 

Strap

AUTO_MDIX_1

IS

(PU)

Port 1 Auto-MDIX Enable Strap: Configures the 
Auto-MDIX functionality on Port 1. When latched 
low, Auto-MDIX is disabled. When latched high, 
Auto-MDIX is enabled.

See 

70

Port 2 Auto-

MDIX Enable 

Strap

AUTO_MDIX_2

IS

(PU)

Port 2 Auto-MDIX Enable Strap: Configures the 
Auto-MDIX functionality on Port 2. When latched 
low, Auto-MDIX is disabled. When latched high, 
Auto-MDIX is enabled.

See 

77-79,

82

General 

Purpose I/O 

Data

GPIO[11:8]

IS/OD12/

O12

(PU)

General Purpose I/O Data: These general 
purpose signals are fully programmable as either 
push-pull outputs, open-drain outputs, or Schmitt-
triggered inputs by writing the 

 and 

. For more information, refer to 

.

The remaining GPIO[7:0] pins share 
functionality with the LED output pins, as 
described in 

 and 

.

63

Interrupt 

Output

IRQ

O8/OD8

Interrupt Output: Interrupt request output. The 
polarity, source and buffer type of this signal is 
programmable via the 

.

71

System Reset 

Input

nRST

IS

(PU)

System Reset Input: This active low signal allows 
external hardware to reset the LAN9311/LAN9311i. 
The LAN9311/LAN9311i also contains an internal 
power-on reset circuit. Thus, this signal may be left 
unconnected if an external hardware reset is not 
needed. When used, this signal must adhere to the 
reset timing requirements as detailed in 

.

The LAN9311/LAN9311i must always be 
read at least once after power-up or reset 
to ensure that write operations function 
properly.