LAN9303 Datasheet, PDF (37/366 Pages) SMSC Corporation – Small Form Factor Three Port 10/100 Managed Ethernet Switch with Single MII/RMII/Turbo MII

Small Form Factor Three Port 10/100 Managed Ethernet Switch with Single MII/RMII/Turbo MII
Datasheet
Table 3.5 GPIO/LED/Configuration Straps (continued)
NUM
PINS
NAME
LED 0
GPIO 0
1
Port 1 Auto-
MDIX Enable
and
LED 0 Polarity
Configuration
Strap
SYMBOL
LED0
GPIO0
AMDIX1_LED0P
BUFFER
TYPE
DESCRIPTION
O12/
OD12/
OS12
This pin is configured to operate as an LED when
the LED 0 Enable bit in the LED Configuration
Register (LED_CFG) is set. The buffer type
depends on the setting of the field in the LED
Configuration Register (LED_CFG) and is
configured to be either an push-pull or open-
drain/open-source output. When selected as an
open-drain/open-source output, the polarity of this
pin depends up the AMDIX1_LED0P strap value
sampled at reset.
IS/O12/
OD12
(PU)
This pin is configured to operate as a GPIO when
the LED 0 Enable bit of the LED Configuration
Register (LED_CFG) is clear. The pin is fully
programmable as either a push-pull output, an
open-drain output, or a Schmitt-triggered input by
writing the General Purpose I/O Configuration
Register (GPIO_CFG) and the General Purpose
I/O Data & Direction Register (GPIO_DATA_DIR).
IS
(PU)
This strap configures the default for the Auto-MDIX
soft-strap for LAN Port 1, as well as the polarity of
the LED 0 pin when it is an open-drain or open-
source output. See Note 3.6.
The strap value determines whether or not LAN
Port 1 Auto-MDIX is enabled as follows:
0 = Disabled
1 = Enabled
For LED 0, If the strap value is 0:
The LED is set as active high, since it is assumed
that a LED to ground is used as the pull-down.
If the strap value is 1:
The LED is set as active low, since it is assumed
that a LED to VDD is used as the pull-up.
Note 3.6
Configuration strap pins are identified by an underlined symbol name. Configuration strap
values are latched on power-on reset or nRST de-assertion. In addition to the configuration
strap pins that control GPIO/LED and Auto-MDIX operation listed in Table 3.5,
configuration strap pins are associated with Port 0 and control its operation. They are
described in Table 3.4. Some configuration straps can be overridden by values from the
EEPROM Loader. Please refer to Section 4.2.4, "Configuration Straps," on page 45 for
further information.
SMSC LAN9303/LAN9303i
37
DATASHEET
Revision 1.3 (08-27-09)