Can am3517 drive 4 8bit DDR2 chip?

Qiang Lee

Other Parts Discussed in Thread: AM3517

Can am3517 drive 4 8-bit ddr2 sdram?

We use 4 8-bit ddr2 sdram, but many errors when I test memory.

Below is the mtest commands output from u-boot:

Mem error @ 0x85BCB200: found 5555AA55, expected 55555555

Mem error @ 0x85BF0200: found 5555AA55, expected 55555555

Mem error @ 0x87B7C200: found 5555AA55, expected 55555555

Mem error @ 0x87BEB200: found 5555AA55, expected 55555555

Mem error @ 0x87DD8100: found 5555AA55, expected 55555555

Mem error @ 0x87DF8100: found 5555AA55, expected 55555555

Mem error @ 0x8DB03200: found 5555AA55, expected 55555555

It seems the second chip goes wrong, but it works most time. And other boards have the same error.

I am not sure whether am3517 can drive 4 DDR2 chips.

over 15 years ago

0 Jeff Culverhouse over 15 years ago

TI__Genius 9190 points

Hello,

Most likely you are violating our load spec with 4 loads. We recommend that no more that the AM35x DDR pins sees no more than 2 loads.

0 Brad Griffis over 15 years ago

TI__Guru*** 125430 points

Here's the pertinent info from the data sheet:

As you can see you have violated the data sheet and so we cannot guarantee correct operation of the device.

Brad

0 Qiang Lee over 14 years ago in reply to Brad Griffis

Prodigy 250 points

Thanks for the reply.

It is the hardware design fault, and now we can drive 4 8-bit DDR2 DRAM. Thanks anyway.

0 Jeff Culverhouse over 14 years ago in reply to Qiang Lee

TI__Genius 9190 points

Hello,

Can you tell me what memories you are using (part numbers)? So that I can make note of these devices?

Thanks!

0 Brad Griffis over 14 years ago in reply to Qiang Lee

TI__Guru*** 125430 points

Qiang Lee said:

Thanks for the reply.

It is the hardware design fault, and now we can drive 4 8-bit DDR2 DRAM. Thanks anyway.

Just to be absolutely clear, you are operating out of the designed/tested range and we cannot guarantee correct operation over temperature, process, and voltage.

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Can am3517 drive 4 8bit DDR2 chip?