SMSC LAN9311 User Manual

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

Revision 1.4 (08-19-08)

138

SMSC LAN9311/LAN9311i

 

This chapter details the LAN9311/LAN9311i serial management functionality of the I

2

C/Microwire

EEPROM Controller and the supporting EEPROM Loader.

The I

2

C/Microwire EEPROM controller is an I

2

C/Microwire master module which interfaces an optional

external EEPROM with the system register bus and the EEPROM Loader. Multiple types
(I

2

C/Microwire) and sizes of external EEPROMs are supported. Configuration of the EEPROM type

and size are accomplished via the eeprom_type_strap and eeprom_size_strap[1:0] configuration straps
respectively. Various commands are supported for each EEPROM type, allowing for the storage and
retrieval of static data. The I

2

C interface conforms to the Philips I

.

The EEPROM Loader provides the automatic loading of configuration settings from the EEPROM into
the LAN9311/LAN9311i at reset. The EEPROM Loader module interfaces to the EEPROM Controller,
Ethernet PHYs, and the system CSRs.

Based on the configuration strap eeprom_type_strap, the I

2

C/Microwire EEPROM controller supports

either Microwire or I

2

C compatible EEPROMs. The I

2

C/Microwire serial management pins functionality

and characteristics differ dependant on the selected EEPROM type as summarized in 

.

When the EEPROM Loader is running, it has exclusive use of the I

2

C/Microwire EEPROM

controller. Refer to 

I

2

C Master 

EEPROM 

Mode

eeprom_type_strap 

= 1

Input enabled 
(to I

2

C master)

Open-drain output 
(from I

2

C master)

Pull-down disabled

Input enabled 
(used for straps)

Output enabled 
(driven low)

Input enabled 
(used for straps)

Output enabled 
(driven low)

Input enabled 
(to I

2

C master and 

used for straps)

Open-drain output 
(from I

2

C master)

Microwire 

Master 

EEPROM 

Mode

eeprom_type_strap 

= 0

Input enabled
(to Microwire master)

Output disabled

Pull-down enabled

Input enabled 
(used for straps)

Output enabled (from 
Microwire master)

Input enabled 
(used for straps)

Output enabled (from 
Microwire master)

Input enabled
(used for straps)

Output enabled (from 
Microwire master)