Selecting a DDR organization

shai kon

Expert 1960 points

Hello,

Suppose I have a microprocessor that I want to connect to DDR3 memory.
The width of the data bus is 32 bits.

Now, I have 2 choices:
1. Split the 32b into 2 groups (16 bits each) and put 2 chips on board.
2. Split the 32b into 4 groups (8 bits each) and put 4 chips on board.

The benefits of the first option are obvious: less power, less space, less layout effort, lower cost.

What are the benefits of the second approach?

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

Hi,

This forum supports only the TI Sitara processor family. Which Sitara processor are you asking about?

0 shai kon over 9 years ago in reply to Biser Gatchev-XID

Expert 1960 points

My inquiry isn't device specific.
But the board I'm designing uses a Sitara processor and I couldn't find a more appropriate place to post my question.

0 Biser Gatchev-XID over 9 years ago in reply to shai kon

TI__Guru**** 393215 points

Well, for example with the AM335X processor you can achieve the maximum memory size of 1GB only if you use 2x8 bit memories.

0 shai kon over 9 years ago in reply to Biser Gatchev-XID

Expert 1960 points

So,
The only motivation to use more chips is memory size ?

0 Biser Gatchev-XID over 9 years ago in reply to shai kon

TI__Guru**** 393215 points

Chip availability could also be a reason.

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Selecting a DDR organization