That is how it was done in the lwIP demo provided by STM, I simply adopted that. The SRAM3 is small, but big enough for lwIP, so all of it is used completely by lwIP. How would you place the descriptors in code so that these linker script sections are not necessary? You mentioned RTEMS_SECTIONs. Are those used in the source code?
Kind Regards Robin Müller On Mon, 22 Mar 2021 at 11:43, Sebastian Huber < sebastian.hu...@embedded-brains.de> wrote: > On 03/02/2021 14:50, Robin Müller wrote: > > > The following link contains more theoretical information about why > > these sections were placed at these addresses: > > > https://community.st.com/s/article/FAQ-DMA-is-not-working-on-STM32H7-devices > > < > https://community.st.com/s/article/FAQ-DMA-is-not-working-on-STM32H7-devices > > > > > > Kind Regards > > Robin > > > > On Wed, 3 Feb 2021 at 14:44, Robin Müller <robin.muelle...@gmail.com > > <mailto:robin.muelle...@gmail.com>> wrote: > > > > The DMA descriptors need to be placed at the start of the SRAM3 > > and need to be aligned in a certain way. The RX buffer will take > > up the first (slightly less than) 16 kB of SRAM3 but needs to be > > placed > > behind the DMA descriptors. It also needs to be placed in a way > > that the MPU configuration required for the DMA descriptors will > > not do something with the RX buffers. > > In the example provided by STM32, the first 256 bytes are > > configured by MPU Config. > > > I had a look at the FAQ and the manual. Currently, we use the SRAM1 for > the .nocache area. This is in the D2 domain. The Ethernet module is in > the D2 domain. I am not sure why you have to change this to the smaller > SRAM3? The libbsd driver works well with the current setting. > > -- > embedded brains GmbH > Herr Sebastian HUBER > Dornierstr. 4 > 82178 Puchheim > Germany > email: sebastian.hu...@embedded-brains.de > phone: +49-89-18 94 741 - 16 > fax: +49-89-18 94 741 - 08 > > Registergericht: Amtsgericht München > Registernummer: HRB 157899 > Vertretungsberechtigte Geschäftsführer: Peter Rasmussen, Thomas Dörfler > Unsere Datenschutzerklärung finden Sie hier: > https://embedded-brains.de/datenschutzerklaerung/ > >
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