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SDRAM AS4C4M16SA initialization failure with STM32F429

Question asked by Mootaz Amr on Feb 10, 2017
Latest reply on Feb 13, 2017 by Mootaz Amr

Hi    ST community



I have a custom made board around an STM32F429IIT6 connected to an external SDRAM AS4C4M16SA, I followed initialization steps embedded in the STM32F429 Reference Manual RM0090 page 1663, and the Power Up sequence described in Note 11 of the AS4C4M16SA datasheet page 20.


The tests I made are simple Write8bits Read8bits functions of an array elements, but attempts always give wrong results if not zeros.


I used previously the MT48LC4M16 chip and it works fine, but the PCB design has changed and the old code doesn't fit the new AS4C4M16SA, the pins of the 2 chips are the same, and connections with the microcontroller are then the same.


The STM32F429 uses its internal clock source, the FMC Controller is feeded with 84MHz clock.


Attached you can find my configuration files and my serial debug results with the hope to find a solution.



If anyone need any further information missing, please comment.


Thanks in advance .