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

Datasheet

2.2.9GPIO/LED Controller

The LAN9311/LAN9311i provides 12 configurable general-purpose input/output pins which are controlled via this module. These pins can be individually configured via the GPIO/LED CSRs to function as inputs, push-pull outputs, or open drain outputs and each is capable of interrupt generation with configurable polarity. Two of the GPIO pins (GPIO[9:8]) can be used for IEEE 1588 timestamp functions, allowing GPIO driven 1588 time clock capture when configured as an input, or GPIO output generation based on an IEEE 1588 clock target compare event.

In addition, 8 of the GPIO pins can be alternatively configured as LED outputs. These pins, GPIO[7:0] (nP1LED[3:0] and nP2LED[3:0]), may be enabled to drive Ethernet status LEDs for external indication of various attributes of the switch ports.

2.3System Configuration

In a typical application, the LAN9311/LAN9311i Host Bus Interface (HBI) is connected to the host microprocessor/microcontroller via the asynchronous 16-bit interface, allowing access to the LAN9311/LAN9311i system configuration and status registers. The LAN9311/LAN9311i utilizes the internal Host MAC to provide a network path for the host CPU. The LAN9311/LAN9311i may share the host bus with additional system memory and/or peripherals. For more information on the HBI, refer to Chapter 8, "Host Bus Interface (HBI)," on page 99.

The 2 Ethernet ports of the LAN9311/LAN9311i must be connected to Auto-MDIX style magnetics for proper operation on the Ethernet network. Refer to the SMSC Application Note 8.13 “Suggested Magnetics” for further details.

The LAN9311/LAN9311i also supports optional EEPROM and GPIOs/LEDs. When an EEPROM is connected, the EEPROM loader can be used to load the initial device configuration from the external EEPROM via the I2C/Microwire interface.

A system configuration diagram of the LAN9311/LAN9311i in a typical embedded environment can be seen in Figure 2.2.

To Ethernet

 

I2C/Microwire

EEPROM

Magnetics

 

 

 

 

(optional)

 

 

 

LAN9311/LAN9311i

 

Microprocessor/

 

Microcontroller

 

 

 

To Ethernet

 

 

 

Magnetics

 

 

 

 

 

 

System

 

 

 

Memory

GPIOs/LEDs

External

 

 

(optional)

 

 

 

25MHz Crystal

 

System

Peripherals

Figure 2.2 System Block Diagram

SMSC LAN9311/LAN9311i

25

Revision 1.4 (08-19-08)

 

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