K70 DDR2 Write Read Problem

[kayathrim]

Hi all,

We are using custom board K70 MCU. Problem in DDR2 write and read in some boards. I am using memory test program to test the DDR2. Configurations of DDR2 remains same as K70 Tower kit. I am shifting bit '1' 8 times at location 0x80000000 for databus test. While reading it 11111111 is not written properly, instead 00000000 is written. I have tested in various address also. How to solve this problem?

We are using DDR2 MT47H64M16HR-3IT:H

Regards,

Kayathri

[pbanta]

Hi,

Do you know if you can successfully write *any* value to 0x80000000?  Forget about shifting bits.  For example, can you write 0xA5A5A5A5 to 0x80000000 and read it back?

Paul

[kayathrim]

Hi Paul,

I wrote 0xA5A5A5A5  at address 0x80000000. if i read back, I am getting 0x25 at location 0x80000000.

1.I have tried to write 0xA5A5A5A5 at entire DDR2 memory location. if i read back, 0x80000000= 0x25 and 0x80000001 = 0xA5.  I have attached screenshot of the memory herewith.

2. At address 0x80000001 if i write value from 00 to FF and read back value is ok.

3. At address 0x80000000 if i write value from 00 to FF and read back upto 7F is ok. For 0x80 to FF value, it is reading 00 to 7F again.

Regards,

Kayathri

[vicentegomez]

Hi Kayathri

if you have some boards that works properly and in other the same software is having problem, this locks like there is a hardware issue on those boards

Please check if there is not some missing  capacitor o component, please also check the lines for the DDR comunication,or maybe if the K70 is properly solder to the PCB

Regards

Vicente

[kayathrim]

Hi Vicente,

We have re-soldered the DDR and K70 doubting that the hardware may have the problems but still the problem continues.

Regards,

Kayathri