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Using 2 device with FSMC?

Question asked by Sandor Bedo on Jun 4, 2018
Latest reply on Jun 4, 2018 by Sandor Bedo



Right now I am facing with the next issue:

I am using FSMC to drive an SDRAM (IS66WV51216) and an LCD (ILI9481 display). As I use only the SDRAM without TFT, the write and read works fine, but as I connect the display the write/read operations have interesting issues.

As I write 1k data in to the SDRAM from 0-1023 and as I read back the numbers are strange (0 0 1 1 7 7 7 7 23 23 ...).

But  as I use only the TFT with FSMC it also works fine.


I use the next settings:

  • NE1, NE2 -> PULL UP
  • DATA [0 - 16] -> PULL DOWN
  • ADDRES[0 - 18] -> NO RESISTOR
  • NWE -> PULL UP
  • NOE -> PULL UP
  • A25 -> this is connected to RS pin of TFT (data or command selector) NO RESISTOR


The data pins from 0-8 bits are common as the NWE and the NOE pins.



The data widths of the devices:

  • TFT => 8 bits
  • SDRAM => 16 bits


So separately both device work, but as I would like to use them in one SW it does not work.

I am using STM32F417ZET6 uC.


Have anybody any idea what should I set up to solve this problem?