Dear all, I started to follow up this topic.
Found that one in sam_hsmci.c: /* There is some unresolved issue with the SAMV7 DMA. TX DMA is currently * disabled. */ #undef HSCMI_NORXDMA /* Define to disable RX DMA */ *#define HSCMI_NOTXDMA 1 /* Define to disable TX DMA */* That fits my (and Michael Lenc's) experience that DMA peripheral to memory works. Memory to the peripheral seems broken though. I will therefore debug *sam_xdmax.c*. Even if I find some odd comments on DMA timeouts in sam_spi.c. If anybody has a better idea, or remembers details ;), please give feedback. BR, Simon -- Hard- and Softwaredevelopment Consultant Ingenieurbüro-Filgis USt-IdNr.: DE305343278 On Tue, Feb 8, 2022 at 11:52 AM Simon Filgis <si...@ingenieurbuero-filgis.de> wrote: > Dear all, > > I'm using ST7789.c in combination with lvgl-lib. > > The bottleneck to the display is the SPI communication. But even if I > increase the SPI frequency to 24MHz, it does not get faster. This is > because of constant delay between the bytes. > > I guessed that this can be improved using DMA. But that does not seem to > work out of the box. In the SPI TX callback the result of the DMA transfer > is -4. The transfer is not executed. > > Can anybody give me a hint on what to do? > > Best regards, > > Simon > > -- > Hard- and Softwaredevelopment Consultant > Ingenieurbüro-Filgis > USt-IdNr.: DE305343278 >
