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SDRAM Issue, using STM Example code, on STM32F769I-EVAL

Question asked by Keenan.Wayne on Jan 6, 2017
Latest reply on Jan 16, 2017 by Keenan.Wayne

I’m running an unmodified FMC_SDRAM example on 2 different STM32F769I-EVAL boards and am seeing the same failures on both, more details below.

 

 

Are there any jumpers or 0-Ohm restores that need to be added or removed?

Has anyone else managed to get it to work?

 

 

Note:  The Camera module and the LCD are removed, just in case.

Note:  The SRAM example works.   

 

Environment

 

Target Board: STM32F769I_EVAL (MB1219 Rev.B)

 

Compiler: 

System Workbench for STM32 - C/C++ Embedded Development Tools for MCU

Version: 1.11.0.201610101240

 

Platform:

vagrant-ubuntu-trusty-64 3.13.0-79-generic  x86_64

 

 

 

 

SDRAM Test

 

Example:   STM32Cube_FW_F7_V1.5.1/Projects/STM32F769I_EVAL/Examples/FMC/FMC_SDRAM

 

4 different variations:

 

a) Running Unmodified

Doesn’t work, all values in the rxBuffer are the same and an unexpected value:

 

Expected:

   Hex:0xa244250f

   Binary:10100010010001000010010100001111

Actual:  

   Hex:0xa244350f 

   Binary:10100010010001000011010100001111

                       

 

b) Sanity test

 

For sanity testing I changed the example to write/read to/from internal RAM instead of SDRAM, this works ok.

 

 

c) Alternate value

Writing 0x00000000 results in an 0x0fe followed by 0xff’s being read back in 'rxBuffer'

 

 

d) Alternate offset

 

I changed the WRITE_READ_ADDR from the default of 0x0800 to 0x0000 and this seems to work, but is worrying as the SDRAM is much larger than 2k so should of worked at 0x0800

 

SRAM Test:

 

This works ok: ~/STM32Cube/Repository/STM32Cube_FW_F7_V1.5.1/Projects/STM32F769I_EVAL/Examples/FMC/FMC_SRAM

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