DP83822I: DP83822EVM, SPEED LED does not work.

Hi Yue,

For SPEED LED is on when connecting to a 100M interface and off when in a 10M network, You need to configure CRS strap in mode 3.

CRS pin is by default PU. Can you try 6.2K for R22 and 1.96K for R24. Depopulate R25. Short both pins of J11.

Regards,
Geet

Geet，

From the datasheet of DP83822I,  I don't  get the association between CSR pin(27) and SPEED LED. as you mentioned, need to configure CRS stap in mode 3, please let me know how to do it.  R22,R24,R25 is related to pin(24), It should not relate to CRS mode 3, right?

BTW, R22 and R24 already had a 2.49K res, is there any reason  of this change? also 1.96K is not very common， can you please suggest another resistor?

Hi,

CRS pin is latched by DP83822 to configure the LED_0 and LED_1. Refer to table 13. Resistors are needed of specific value and 1% precision to latch the correct mode.

In my earlier post, I mistakenly asked to change the straps on LED_0 pin. Instead this shall be done on CRS pin straps shown in J14.

Regards,

Geet

so, 6.2K for R53 and 1.96K for R55. No other modification need, right?

so, 6.2K for R53 and 1.96K for R55. No other modification need, right?

I close this thread first. Thanks for the reply. 

Geet, 

I successfully read out the register 0x0460, the value is 0x0551. it matches the default value of datasheet. actually, the default function of LED_1  is 

0101 = Speed, High for 100Base-TX.   can you please suggest how to just change the register to get what I want?

HI,

 We use USB-MDIO Software Tool. It needs a MSP430F5529 LaunchPad to connect to DP83822 evm.

Regards,

Geet

Yes. I can successfully use USB-MDIO tool.  just want to know which registers I need to modify to get the SPEED light work as expected. seem the default value of 0x0460 should turn on the SPEED light, but I can't see the light up.  I also did some modification , but no reaction at all.

You have to select extended address space in GUI.

Regards,
Geet