topic Re: K70 LCDC flicker when writing to DDR2 memory in Kinetis Microcontrollers https://community.nxp.com/t5/Kinetis-Microcontrollers/K70-LCDC-flicker-when-writing-to-DDR2-memory/m-p/457532#M27273 <HTML><HEAD></HEAD><BODY><P>Hello Carl,</P><P></P><P>Please check the below thread.</P><P><A href="https://freescale.jiveon.com/thread/334337" title="https://freescale.jiveon.com/thread/334337">Pixel delayed on K70 - MQX - PEG | Freescale Community</A> </P><P><BR />Have a great day,<BR /> Sol <BR /> <BR />-----------------------------------------------------------------------------------------------------------------------<BR />Note: If this post answers your question, please click the Correct Answer button. Thank you!<BR />-----------------------------------------------------------------------------------------------------------------------</P></BODY></HTML> Wed, 27 May 2015 20:02:04 GMT soledad 2015-05-27T20:02:04Z K70 LCDC flicker when writing to DDR2 memory https://community.nxp.com/t5/Kinetis-Microcontrollers/K70-LCDC-flicker-when-writing-to-DDR2-memory/m-p/457531#M27272 <HTML><HEAD></HEAD><BODY><P>I have a custom board with a K70 processor connected to a TFT display (320*240*24bpp) using the LCDC controller. The LCDC reads pixel data from an 8MB DDR2 memory. I use PEG Lite and MQX 4.1. The processor is running in 120Mhz and the DDR2 memory in 150Mhz.</P><P></P><P>I have a problem with flicker on the display when I write to the DDR2 memory (I am not writing to the display buffer but a competely different area in the same memory). As soon as I stop writing the flicker stops.</P><P></P><P>It feels like the display controller is not able to read data from the DDR2 memory fast enough when other memory operations are performed to the same memory. </P><P></P><P>A very strange thing is that writing 32-bit data does not cause any flicker, only writing 16-bit or 8-bit data.</P><P></P><P>I have tried som ideas from this forum but nothing works:</P><P>* double buffer and frame-sync in PEG on/off<BR />* configuring the crossbar switch priorities to give lcdc highest priority and also using round-robin scheduling<BR />* flushing the caches in the display driver <BR />* testing with different pixel clocks from 6 to 10Mhz for the display<BR />* make sure data and instruction cache are activated<BR />* activating burst-mode for lcdc transfers</P><P></P><P>Do you have any idea what could cause a problem like this?</P></BODY></HTML> Sat, 23 May 2015 11:01:43 GMT https://community.nxp.com/t5/Kinetis-Microcontrollers/K70-LCDC-flicker-when-writing-to-DDR2-memory/m-p/457531#M27272 carl-magnusmoon 2015-05-23T11:01:43Z Re: K70 LCDC flicker when writing to DDR2 memory https://community.nxp.com/t5/Kinetis-Microcontrollers/K70-LCDC-flicker-when-writing-to-DDR2-memory/m-p/457532#M27273 <HTML><HEAD></HEAD><BODY><P>Hello Carl,</P><P></P><P>Please check the below thread.</P><P><A href="https://freescale.jiveon.com/thread/334337" title="https://freescale.jiveon.com/thread/334337">Pixel delayed on K70 - MQX - PEG | Freescale Community</A> </P><P><BR />Have a great day,<BR /> Sol <BR /> <BR />-----------------------------------------------------------------------------------------------------------------------<BR />Note: If this post answers your question, please click the Correct Answer button. Thank you!<BR />-----------------------------------------------------------------------------------------------------------------------</P></BODY></HTML> Wed, 27 May 2015 20:02:04 GMT https://community.nxp.com/t5/Kinetis-Microcontrollers/K70-LCDC-flicker-when-writing-to-DDR2-memory/m-p/457532#M27273 soledad 2015-05-27T20:02:04Z