SDRAM AS4C4M16SA initialization failure with STM32F429

[Mootaz Amr]

Posted on February 10, 2017 at 17:45

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

http://www.st.com/content/ccc/resource/technical/document/reference_manual/3d/6d/5a/66/b4/99/40/d4/DM00031020.pdf/files/DM00031020.pdf/jcr:content/translations/en.DM00031020.pdf

 page 1663, and the Power Up sequence described in Note 11 of the AS4C4M16SA

http://www.alliancememory.com/pdf/dram/64M-AS4C4M16SA.pdf

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 .

#as4c4m16sa #stm32f429 #sdram

[Tesla DeLorean]

Posted on February 10, 2017 at 18:50

Here's a tip ZIP up all the files you want to attach, and then attach ONE file. 

Is there a strong reason the slew rate was increased to 100 MHz rather than being left at 50 MHz. Given the trace length are going to be rather short the higher rate is probably not desirable and will introduce overshoot/ringing. The logic that 84 MHz > 50 MHz doesn't work here.

[Mootaz Amr]

Posted on February 13, 2017 at 17:18

Thanks Clive.

Great remark, I returned it back to 50MHz, but what about the configuration, is there a missing thing ?

You can find here my schematic uploaded so you can have adeeper idea. ________________ Attachments : Schematic and config Files.rar : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006HxbH&d=%2Fa%2F0X0000000bE4%2FyOumalCmuuKygjfl__d_jTYvOnVsLI0OEbHL7w8Wm1Q&asPdf=false