DP83822I: Parallel pull-up and pull-down resistor for LED

NAOKI AOYAMA

Guru 11215 points

Part Number: DP83822I

Hello,

Our customer use the DP83822.

They configure the LED_0 and LED_1 as Mode2.

So they connect resistor to CRS pin as pull-up:13kohm and pull-down 1.96kohm.

They use the DP83822 with 100BASE-TX Full duplex.

It should set the LED_0 pin as Mode3. So it should be connected resistor to LED_0 pin

as pull-up 6.2kohm and pull-down 1.96kohm.

In this configuration, does the LED_0 pin recognize the pull-down resistor and

configured as an active high driver?

*Because the condition of our network is bad, I'm sorry if the posts have been doubled.

Best Regards,

Naoki Aoyama

over 6 years ago

0 Geet Modi over 6 years ago

TI__Mastermind 26320 points

Hi,

In general, at reset, LED pin detect external Pull resistor and accordingly decides to be active Low or active High.
Active high driver on LED_0 pin will be based on the PU/PD on the pin for strap. What is the strap resistor values on LED_0 and LED_1 to set in MOde 2 ?

Regards,
Geet

0 NAOKI AOYAMA over 6 years ago in reply to Geet Modi

Guru 11215 points

Hello Geet,

Thank you for your reply.

The LED_0 pin is also bootstrap pin for configure the AN_0 (Mode of Operation).
Now, the LED_0 pin set the pull-up 6.2kohm and pull-down 1.96kohm.
Which does the LED_0 pin recognize pull-up or pull-down?

Regards,
Naoki Aoyama

0 NAOKI AOYAMA over 6 years ago in reply to Geet Modi

Guru 11215 points

Hello Geet,

Could you give me the answer?

Regards,
Naoki Aoyama

0 Geet Modi over 6 years ago in reply to NAOKI AOYAMA

TI__Mastermind 26320 points

Hi Naomi-San,

I am looking in and get back in couple of days.

Regards,

Geet

0 Geet Modi over 6 years ago in reply to Geet Modi

TI__Mastermind 26320 points

Hi Naomi-san,

For LED_0, both strap mode 3 an 4 can be used to enable AN_0. Instead of Mode 3, ask you customer to use Mode 4 which is default as well and no external PU/PD will be needed. Customer can connect LED with resistor in series.

Regards,
Geet

0 NAOKI AOYAMA over 6 years ago in reply to Geet Modi

Guru 11215 points

Hello Geet,

Thank you for your reply.
I see it's a good idea.
I will ask the customer to use Mode4.

Thanks,
Naoki Aoyama

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DP83822I: Parallel pull-up and pull-down resistor for LED