DP83822I: LED configuration

Wendy Wang1

Mastermind 18695 points

Part Number: DP83822I

Hi team,

About DP83822, I have a few questions on LED configuration.

We target to implement mode2 as below:

Configure CRS:

Strap pins LED0/LED1 are both used default configuration without external pull up or pull down resistors:

I find description about LED in datasheet, but do not well understand it:

Then I should use the circuit for pull up for LED_0, and use circuit for pull down for LED_1, am I right? Is the LED_1 pin should be take as a pulled down pin? Does the parallel resistor for LED effect the strap result?

Best regards,

Wendy

over 4 years ago

+1 Kallikuppa Sreenivasa over 4 years ago

TI__Guru**** 207130 points

Hello Wendy,

Thank you for the query.

The parallel resistor is not expected to have any effect on the pin strapping.

Please ensure the LED polarities match the strapping since the active high and low configuration is decided by the strap.

Regards,

Sreenivasa

0 Wendy Wang1 over 4 years ago in reply to Kallikuppa Sreenivasa

TI__Mastermind 18695 points

Hi Sreenivasa,

Nice to meet you here!

Thanks for your help! I also want to check the LED_1 pin, should it be taken as active H or L when driving an external SPEED indicator LED?

Best regards,

Wendy

+1 Kallikuppa Sreenivasa over 4 years ago in reply to Wendy Wang1

TI__Guru**** 207130 points

Hello Wendy

Good morning. Nice to meet you and talk to you.

Please see below:

Mode 2: SPEED Indication, LED indicates the speed of the link. If speed is 100 Mbps, LED is ON. If speed is 10 Mbps, LED is OFF. External Pull resistors are required when LED is connected to this pin.

regards,

Sreenivasa

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DP83822I: LED configuration