AM3359: How to enable CLKOUT2 in dts

Shine

Part Number: AM3359
Other Parts Discussed in Thread: CDCE913,

Hello,

1. Customer used AM3359 dual MAC: RGMII and RMII。CDCE913 provides 50MHz to RMII, but the minimum fvco of cdce913 is 80MHz, how to configure it to output 50MHz。

2. Connnecting RMII clock to CLKOUT2 pin, the source of CLKOUT2 pin is l3_gclk, then divided by 4. How to configure the dts file to output clock from CLKOUT2?

SDK is the latest 06.03.

Modify the dts file:

&clkout2_div_ck {

clocks = <&l3_gclk>;
ti,dividers = <4>;
};

&am33xx_pinmux {
pinctrl-names = "default";
pinctrl-0 = <&clkout2_pin>; /* eth1时钟 */

clkout2_pin: pinmux_clkout2_pin {
pinctrl-single,pins = <
0x1b4 (PIN_OUTPUT_PULLDOWN | MUX_MODE3) /* xdma_event_intr1.clkout2 */
>;
};

But there is no output from CLKOUT2 pin.

Thanks.
Rgds

Shine

over 3 years ago

0 Biser Gatchev-XID over 3 years ago

TI__Guru**** 393215 points

Hi,

1. CDCE913 is not supported on this forum. Please ask this question on the Clock & Timing forum: https://e2e.ti.com/support/clock-and-timing/f/48

2. CLKOUT2 should not be used as a RMII clock source. Section 8.1.6.12 od the AM335x TRM Rev. Q states:

"The CLKOUT1 and CLKOUT2 signals go to device pads and should mainly be used as debug testpoints. Using these signals for time-critical external circuits is discouraged because of unpredictable jitter performance."

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AM3359: How to enable CLKOUT2 in dts