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

Datasheet

14.2.3GPIO/LED

This section details the General Purpose I/O (GPIO) and LED related System CSR’s.

14.2.3.1General Purpose I/O Configuration Register (GPIO_CFG)

Offset:

1E0h

Size:

32 bits

This read/write register configures the GPIO input and output pins. The polarity of the 12 GPIO pins is configured here as well as the IEEE 1588 timestamping and clock compare event output properties of the GPIO[9:8] pins.

BITS

 

DESCRIPTION

TYPE

DEFAULT

 

 

 

 

31:30

RESERVED

RO

-

 

 

 

 

29:28

GPIO 1588 Timer Interrupt Clear Enable 9-8

R/W

00b

 

(GPIO_1588_TIMER_INT_CLEAR_EN[9:8])

 

 

 

These bits enable inputs on GPIO9 and GPIO8 to clear the

 

 

 

1588_TIMER_INT bit of the 1588 Interrupt Status and Enable Register

 

 

 

(1588_INT_STS_EN). The polarity of these inputs is determined by

 

 

 

GPIO_INT_POL[9:8].

 

 

 

Note:

The GPIO must be configured as an input for this function to

 

 

 

 

operate. For the clear function, GPIO inputs are edge sensitive and

 

 

 

 

must be active for greater than 40 nS to be recognized.

 

 

 

 

 

 

27:16

GPIO Interrupt Polarity 11-0 (GPIO_INT_POL[11:0])

R/W

0h

 

These bits set the interrupt polarity of the 12 GPIO pins. The configured

 

 

 

level (high/low) will set the corresponding GPIO_INT bit in the General

 

 

 

Purpose I/O Interrupt Status and Enable Register (GPIO_INT_STS_EN).

 

 

 

0: Sets low logic level trigger on corresponding GPIO pin

 

 

 

1: Sets high logic level trigger on corresponding GPIO pin

 

 

 

GPIO_INT_POL[9:8] also determines the polarity of the GPIO IEEE 1588

 

 

 

time clock capture events and the GPIO 1588 Timer Interrupt Clear inputs.

 

 

 

Refer to Section 13.2, "GPIO Operation," on page 163 for additional

 

 

 

information.

 

 

 

 

 

 

15:14

1588 GPIO Output Enable 9-8 (1588_GPIO_OE[9:8])

R/W

0h

 

These bits configure GPIO 9 and GPIO 8 to output 1588 clock compare

 

 

 

events.

 

 

 

 

0: Disables the output of 1588 clock compare events

 

 

 

1: Enables the output of 1588 clock compare events

 

 

 

Note:

These bits override the direction bits in the General Purpose I/O

 

 

 

 

Data & Direction Register (GPIO_DATA_DIR) register. However,

 

 

 

 

the GPIO buffer type (GPIOBUF[11:0]) in the General Purpose I/O

 

 

 

 

Configuration Register (GPIO_CFG) is not overridden.

 

 

 

 

 

 

13

GPIO 9 Clock Event Polarity (GPIO_EVENT_POL_9)

R/W

1b

 

This bit determines if the 1588 clock event output on GPIO 9 is active high

 

 

 

or low.

 

 

 

 

0: 1588 clock event output active low

 

 

 

1: 1588 clock event output active high

 

 

 

 

 

 

12

GPIO 8 Clock Event Polarity (GPIO_EVENT_POL_8)

R/W

1b

 

This bit determines if the 1588 clock event output on GPIO 8 is active high

 

 

 

or low.

 

 

 

 

0: 1588 clock event output active low

 

 

 

1: 1588 clock event output active high

 

 

 

 

 

 

 

SMSC LAN9311/LAN9311i

193

Revision 1.4 (08-19-08)

 

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