STM32F765 Ethernet stop working increasing MCU clock

raffin · ‎2017-09-01

Posted on September 01, 2017 at 17:37

Hi All,

I am working on a custom board using the STM32F765.

The ethernet peripheral is based on DP83620 connected in RMII.

In my application the ethernet is working as the AHB clock is below 190MHz, then it stops to work. I am still trying to understand what happens, for sure when it does not work no data is transmitted. Sometimes reading the status flag of the IC, I read the no link.

It seems and HW problem but I cant figure the reason.

I wonder if it could be related to the silicon errata. I have the silicon 'Z' revision.

waclawek.jan · ‎2017-09-01

Posted on September 01, 2017 at 19:00

How is ETH_MACMIIAR.CR set?

JW

raffin · ‎2017-09-04

Posted on September 04, 2017 at 10:56

Thank you JW for the answer.

I had the same doubt before, it was the first thing I checked. But this register is set correctly, the CR bits are 100, i.e. ETH_MACMIIAR_CR_Div102.

I can't figure where the problem could be.

mario

waclawek.jan · ‎2017-09-04

Posted on September 04, 2017 at 11:44

Hummm.

Tell us more about the ETH clocks.

JW

raffin · ‎2017-09-04

Posted on September 04, 2017 at 17:11

Hi JW,

The ETH clock is provided by the 25 MHz HSE clock. The STM32F765 outputs the 25 MHz from MCO1 and provides this clock to the DP83620.

The DP83620, configured in RMII master mode, generates the 50MHz RX_CLK, TX_CLK and CLK_OUT (not used).

mario

waclawek.jan · ‎2017-09-04

Posted on September 04, 2017 at 17:32

Sounds reasonable.

Unfortunately, my ETH 'expertise' stops here... you probably have to connect your ST FAE/distributor or ask for help through the online form.

JW

raffin · ‎2017-09-05

Posted on September 05, 2017 at 09:26

Thank you for the support, anyway.

Regards,

mario