High Performance Two Port 10/100 Managed Ethernet Switch with 32-Bit Non-PCI CPU Interface
Datasheet
Chapter 10 Serial Management
10.1
Functional 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.
10.2
I2C/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
EE_SDA
EEDO PIN
NOT USED
EECS PIN
NOT USED
EE_SCL/EECLK PIN
EE_SCL
I2C Master
EEPROM
Mode
Input enabled
(to I2C master)
Input enabled
(used for straps)
Input enabled
(used for straps)
Input enabled
(to I2C master and
used for straps)
Open-drain output
(from I2C master)
Output enabled
(driven low)
Output enabled
(driven low)
eeprom_type_strap
= 1
Open-drain output
(from I2C master)
Pull-down disabled
Microwire
Master
EEPROM
Mode
EEDI
EEDO
EECS
EECLK
Input enabled
(to Microwire master) (used for straps)
Input enabled
Input enabled
(used for straps)
Input enabled
(used for straps)
Output disabled
Output enabled (from
Microwire master)
Output enabled (from
Microwire master)
Output enabled (from
Microwire master)
eeprom_type_strap
= 0
Pull-down enabled
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 1.2 (04-08-08)
DATASHEET
SMSC [ SMSC CORPORATION ]
