DP83822I: LED_ 0 Digital transistor connection

Kenji Ohno1

Genius 5095 points

Part Number: DP83822I

Hi Team,

Customers attach digital transistors to the LED_ 0 port for LED drive.

At startup, the voltage of LED_ 0 (Strap pin) becomes 1 V, serial communication is not performed.

If they do not connect a digital transistor to LED_ 0, make sure to communicate with the MAC.

· Can I add a digital transistor to LED_ 0, LED_ 1?

· What happens when the LED_0, LED_1 does not belong to the range of MODE 1 ~ 4, when the strap voltage is?

Best Regards,

Kenji

over 7 years ago

0 Geet Modi over 7 years ago

TI__Mastermind 26320 points

HI Kenji-san,

Can you explain what you mean by digital transistor ? To change the voltage level ?

LED_0 and LED_1 only supports Mode 1 and 4 straps. They do not have mid level straps as mid level strap hampers with LED operations.

Regards,
Geet

0 Kenji Ohno1 over 7 years ago in reply to Geet Modi

Genius 5095 points

Hi Geet-san,

LED_ 0, 1 of PHY is connected to 2 pins and 5 pins of digital transistor.

I don't know why, but when it is OPEN it is 5 V, but the voltage drops to 1 V when connected.

RX_CLK does not oscillate and communication with the MAC is also not performed.

emh60-e.pdf

Best Regards,

Kenji

0 Geet Modi over 7 years ago in reply to Kenji Ohno1

TI__Mastermind 26320 points

HI Kenji-san,

I will wait for your further debug info.

Regards,
Geet

0 Kenji Ohno1 over 7 years ago in reply to Geet Modi

Genius 5095 points

Geet-san,

I'm sorry, I don't have more information than the above.
Can you see how the device will behave when LED_ 0 is 1 V?

Regards,
Kenji

0 Geet Modi over 7 years ago in reply to Kenji Ohno1

TI__Mastermind 26320 points

Hi Kenji-san,

Device is characterise as per datasheet limits.

Regards,
Geet

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DP83822I: LED_ 0 Digital transistor connection