DP83822I: Output 125MHz CLK from COL2/GPIO2 pin for CPU as a reference clock

Harson

Part Number: DP83822I

Hi, Team

I have a question from customer, they use i.Max 6 with DP83822I, the CPU need a 125MHz CLK, customer wants to get this 125MHz clock from DP83822I, datasheet has description that COL2/GPIO2 could support 125MHz output as a recovered clock or free running clock.

They use DP83822I in RGMII mode.

Does it support this function?

Should customer use Recovered clock or free running clock?

What is the difference?

over 5 years ago

0 Vibhu Vanjari over 5 years ago

TI__Genius 11900 points

Hello Harson,

DP83822 does support RGMII, 100BASETX and 10BASE-Te but not gigabit.

The free-running clock is internal to the PHY, while the recovered clock is synchronous to data being transmitted. What clock to use depends on the application.

Thanks,

Vibhu

0 Harson over 5 years ago in reply to Vibhu Vanjari

TI__Expert 3700 points

Vibhu

Customer wants to use RGMII at 100Mbps.

But there is an AP has requirement of reference with 125MHz.

So does it support output 125MHz from this pin?

Like a PLL generate fro 25MHz to 125MHz.

0 Geet Modi over 5 years ago in reply to Harson

TI__Mastermind 26320 points

Hi,

You can use any of the GPIO/LED to get a 125 MHz free running clock.

Please refer to register 0x0462 ( IO MUX GPIO Control Register #1 (IOCTRL1).

regards,

Geet

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DP83822I: Output 125MHz CLK from COL2/GPIO2 pin for CPU as a reference clock