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bjorn2
Associate II
September 5, 2019
Solved

STM32H753 ethernet DMA is not releasing software reset, all clocks are enabled

  • September 5, 2019
  • 1 reply
  • 1340 views

Hi,

I have a ethernet project running on a H743 and H753. The H743 is working fine. The H753 is not working.

If the ETH_MAC clock is enabled I can see that the SWR bit in the DMAMR is set (software reset) and as soon as the RMII is selected as interface ( HAL_SYSCFG_ETHInterfaceSelect(SYSCFG_ETH_RMII); ) the SWR bit is reset by hardware. However, at the H753 the SWR bit is not cleared and the HAL driver will fail because of this sticked SWR bit.

I have checked if all clocks (ETH_TX, ETH_RX and ETH_MAC) are enabled and this is the case. 

What is going wrong?

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Best answer by bjorn2

Ok, ref_clk was missing (pulldown was not mounted for the LAN8742.

1 reply

bjorn2
bjorn2AuthorBest answer
Associate II
September 5, 2019

Ok, ref_clk was missing (pulldown was not mounted for the LAN8742.