Does the AM335x DDR controller support "precharge all" command?

RY9983

Hello.

I would like to use DDR2 memory on AM335x.
There is a reg_t_rp(tRP) field in the SDRAM_TIM_1 register, which is used as precharge command.
But, there is not a field of tRPA which is used as precharge all command.

I think that the AM335x does not support precharge all command.
So, tRPA field is not needed. Is that right?

Best regards, RY

over 12 years ago

0 Biser Gatchev-XID over 12 years ago

TI__Guru**** 393215 points

Hi RY,

There is a tool for calculating DDR timing registers, which can be found here: http://processors.wiki.ti.com/images/a/a4/AM335x_DDR_register_calc_tool.zip. Following the DDR2 design guidelines (AM335X Datasheet, section 5.5.2.2) and the http://processors.wiki.ti.com/index.php/AM335x_EMIF_Configuration_tips is all that's needed to integrate successfully DDR2 memory on a custom board.

0 RY9983 over 12 years ago in reply to Biser Gatchev-XID

Guru 10570 points

Biser-san,

Thank you so much for your answer.
I checked tips and calc tool. It will be helpful for me. Thank you.

But, you know that there is not a field for tRPA on DDR settings.
I am wondering that whether it is no problem.
How do you think about my thinking?

RY9983 said:

I think that the AM335x does not support precharge all command.
So, tRPA field is not needed. Is that right?

Best regards, RY

0 peaves over 12 years ago in reply to RY9983

TI__Guru 63175 points

The precharge all command is supported and tPRA will be tPR + 1, which complies with JEDEC specifications.

Regards,
Paul

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Does the AM335x DDR controller support "precharge all" command?