F767 ethernet errata and DBGMCU_CR

[Uwe Bonnes]

Posted on June 22, 2017 at 14:35

Hello,

the Ethernut (

http://www.ethernut.de)

STM32 Ethernet driver from svn head (/sourceforge.net/projects/ethernut/files/) works reliable for F107/F2/F4 and F74. However for F767 Revision A chip (no Rev Z chips available here), it does not start reliable, obvious caused by the F76 errata.

With DBGMCU->CR set to DBGMCU_CR_DBG_SLEEP | DBGMCU_CR_DBG_STOP | DBGMCU_CR_DBG_STANDBY, at least after some few System Resets, the network comes up.

With DBGMCU->CR set to 0, a long row of resets does _not_ bring up the network.

Did anybody else make this observation?

How do other people recover from the Rev. A F76x ethernet errata?

[Tilen MAJERLE]

Posted on June 27, 2017 at 12:12

Hello

Bonnes.Uwe

‌

We released a new revision Z of this device to solve the main problem with ethernet because there was no workaround.

This also applies to F77x devices.

[Uwe Bonnes]

Posted on June 27, 2017 at 13:18

As a small customer there are two problems:

- what to do with Rev. A chips and boards you already have?

- how to be sure you get Rev. Z chips and boards when buying in single/small quantities?

So some 'hacker' workaround and some notes about requirements needed for this workaround may help others. That was also intended with my post.

[Tilen MAJERLE]

Posted on June 29, 2017 at 10:45

Hello

Bonnes.Uwe

‌,

when ordering device via your local distributor, request Z revision.

Ethernet peripheral had problems on RMII interface, on MII this was not the case. Errata sheet

http://www.st.com/content/ccc/resource/technical/document/errata_sheet/group0/23/a6/11/0b/30/24/46/a5/DM00257543/files/DM002575pdf/jcr:content/translations/en.DM002575pdf

can provide you possible solutions you may do if they fit to your project, otherwise you should create new boards with new revision.

Best regards,

Tilen