Which memory chip on the Arty?

[D@n]

I'm trying to figure out which DDR3 memory chip is on the Arty.  According to the schematic, the Arty has the MT41K128M16JT-125K DDR3 memory chip.  According to the MIG project file I downloaded, however, the chip is the -15E.  The difference between the two chips is significant, as one runs at a 1600 rate, whereas the other runs at 1333.  The MIG project file appears to be designed for the 1333 data rate, but this would be inappropriate if the chips is the -125K chip.

Can you tell me which chip is actually on the Arty?

Thanks!

Dan

[Bianca]

Hi Dan,

The Arty board is equipped according to the schematics with the MT41K128M16JT-125K DDR3 memory chip. If you look in the datasheet of Micron you can see that this chip is backward compatible with the -15E that you can find on the MIG.

 

 

It seems that Xilinx does not have this chip and the other variant of -125 can't be powered at 1.35V.  That is why we recommend using the -15E as said in the reference manual. It is a difference of data rate as you said above, however, the board is equipped with an Artix7 (xc7a35ticsg324-1L) which is the low voltage version. If you look in the datasheet of the FPGA you can see that the data rate for the DDR3L is 667Mb/s

 

 

Even if you could access the chip that you wanted from the MIG you will still be limited by the FPGA capabilities. This is what we also said in the recommendation of configuring the MIG from the Arty reference manual.

 

 

Best regards,

Bianca

 

 

[D@n]

Bianca,

Thank you for a well explained answer.  Now I understand what's going on.

Dan

[Bianca]

Anytime! Let me know if you have further questions.

Bianca