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Interference when using SSD1963 and SDRAM over FMC

Question asked by raggini.davide on Sep 19, 2014
Latest reply on Sep 23, 2014 by raggini.davide
Hi everyone, 
This is my first post on this community, that i found great, so before everything let me say thank you.
I'm currently working on a spare time project which involve some basic PID simulated control/process a simple graphic interface.

I'm starting from the display low level driver, the display is a 800x480 24bit (used as 16bit 565) driven by an SSD1963 [BuyDisplay ER-TFTM070-4V2.1 + CPTouch] over the FMC bus and no problem.
Next i wrote the driver for the SDRAM [64Mb embedded in the STM32F429i-Disco] and also here no problem.
Strange things are happening when i use the two things together; i'm planning to use SDRAM as a frame buffer which send data to the SSD1963 over the DMA mem-to-mem. 

To analyze the situation i made a simple main.c that initialize the SSD (OK) and then the SDRAM with a complete cycle of writing/reading and during this it seems like the /CS of the SSD never get down and all the fast data stuff that runs in the FMC Data bus are also delivered to the SSD. 
Maybe someone of you already had this problem and can help me, i've done pretty much everything but with none result, the strange behavior remains.

I'm here to answer to all your questions, and if you want to look the code i' ve posted the complete and working Coocox project. 

Thank you,
Davide Raggini