DP83826E: how to do LED0, LED1 strap circuit.

Hi Robin, 

LED0 and LED1 pins are pull-down during power-up and reset. 

The LED schematics in the DP83826EVM are shown for active high configuration. If an LED pin is strapped LOW, the pin will operate as active high during normal operation. If an LED is strapped HIGH, the pin will operate as active low. 

To enable LED1, you can strap it high and use a schematic similar to the one below for active low operation.

Regards,
Justin 

hi Justin,

Thanks for the reply. and i still have some question as below?

1) double check that, i see the table below that, LED0 and LED1 is the default 1 pin, it's pull up pin, so why you said, it is pull-down during power-up?

2) "If an LED pin is strapped LOW, the pin will operate as active high during normal operation. If an LED is strapped HIGH, the pin will operate as active low. ", if this description is from the datasheet?

3) could I know which documents the Figure 31. you showed come from?

Thanks & Best regards,

Robin Liu

Hi Robin,

Thank you for your questions. I see a discrepancy between the pin description table and the strap configuration table and will work to address this in the future.

1. The default pin state of these pins can change between Basic Mode and Enhanced Mode. I recommend placing external strap resistors on the LED pins to ensure they strap into the desired state on power-up and reset. 

2. & 3. I am referencing the DP83822I datasheet in the description and diagram above. 

Regards,
Justin 

hi Justin,

OK. The DP83822I is 4-level bootstrap while DP83826E is 2 level strap, it's no problem to follow the DP83822I design guide?

if you are exactly confirmed on this? or you need more double check?

regards,

Robin Liu