RMII Mode link problem

[gabay.1]

I'm using STM32F407 and Marvel 88E6390X switch in our project. But we have some I2C problems so we added I2C recovery function using TIMER8. The ethernet ports doesn't work stable after this addition . When we removed the I2C function in the project , the problem doesn't appear yet . We want to learn where is the problem in the project.

[waclawek.jan]

> But we have some I2C problems so we added I2C recovery function using TIMER8.

What exactly is that "I2C recovery function"?

> The ethernet ports doesn't work stable after this addition .

What does this mean?

JW

[Imen.D]

Hello @gabay.1​ ,

The TIM8 pins are taken by other peripherals on the STM32F407 board.

Please check the free I/O pins in the table "STM32 pin description versus board functions" described in the UM1472 User manual Discovery kit with STM32F407VG MCU.

If a post answers your question, please mark it as Best to close this thread.

Imen

[gabay.1]

@Imen DAHMEN​  Hi Imen . Firstly , we are thank you but we don't use discovery board, we design our boards.

[gabay.1]

We used TIMER8 as a counter for us delay operation. We are using ethernet in RMII mode. In the beginning of the software , we configure ports of  Marvel 88E6390X switch , but some ports doesn't configure sometimes .We understood that the ports don't configure status register. When we turn off the TIMER8 , the ports can be configurable .There is no problem .So , we think there is a connection between ethernet module and TIMER8 .

[waclawek.jan]

> So , we think there is a connection between ethernet module and TIMER8 .

You can test this hypothesis: use some other timer (or maybe DWT's cycle counter) for the us delay, or use just simple loopdelay for the us delay.

JW

[Ashi]

Hi , I am faced with interfacing stm32f7 with same Marvel switch. Could you please share sample code on how to initialize the Marvel switch. Mine is stuck in HAL_ethernet_init after we did a reset using a gpio pin connected to chips reset.

Any help is appreciated.