High Performance Two Port 10/100 Managed Ethernet Switch with 32-Bit Non-PCI CPU Interface

Datasheet

Chapter 10 Serial Management

10.1Functional Overview

This chapter details the LAN9312 serial management functionality of the I2C/Microwire EEPROM Controller and the supporting EEPROM Loader.

The I2C/Microwire EEPROM controller is an I2C/Microwire master module which interfaces an optional external EEPROM with the system register bus and the EEPROM Loader. Multiple types (I2C/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 I2C interface conforms to the Philips I2C-Bus Specification.

The EEPROM Loader provides the automatic loading of configuration settings from the EEPROM into the LAN9312 at reset. The EEPROM Loader module interfaces to the EEPROM Controller, Ethernet PHYs, and the system CSRs.

10.2I2C/Microwire Master EEPROM Controller

Based on the configuration strap eeprom_type_strap, the I2C/Microwire EEPROM controller supports either Microwire or I2C compatible EEPROMs. The I2C/Microwire serial management pins functionality and characteristics differ dependant on the selected EEPROM type as summarized in Table 10.1.

Table 10.1 I2C/Microwire Master Serial Management Pins Characteristics

EEPROM

 

 

 

 

TYPE/MODE

EE_SDA/EEDI PIN

EEDO PIN

EECS PIN

EE_SCL/EECLK PIN

 

 

 

 

 

I2C Master

EE_SDA

NOT USED

NOT USED

EE_SCL

EEPROM

Input enabled

Input enabled

Input enabled

Input enabled

Mode

(to I2C master)

(used for straps)

(used for straps)

(to I2C master and

eeprom_type_strap

Open-drain output

Output enabled

Output enabled

used for straps)

= 1

(from I2C master)

(driven low)

(driven low)

Open-drain output

 

Pull-down disabled

 

 

(from I2C master)

 

 

 

 

 

 

 

 

 

Microwire

EEDI

EEDO

EECS

EECLK

Master

Input enabled

Input enabled

Input enabled

Input enabled

EEPROM

(to Microwire master)

(used for straps)

(used for straps)

(used for straps)

Mode

Output disabled

Output enabled (from

Output enabled (from

Output enabled (from

 

eeprom_type_strap

Pull-down enabled

Microwire master)

Microwire master)

Microwire master)

= 0

 

 

 

 

 

 

 

 

 

 

 

 

Note: When the EEPROM Loader is running, it has exclusive use of the I2C/Microwire EEPROM controller. Refer to Section 10.2.4, "EEPROM Loader" for more information.

SMSC LAN9312

137

Revision 1.4 (08-19-08)

 

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