AM37xx SDRAM status register read

Gunter Schmer

Hi all,

a customer is using the AM37xx platform and is looking for a way to read the SDRAM status register. This is something that is defined in JEDEC as optional, so we are wondering whether it is implemented in the SDRC. It should look something like this:

Status Register Read

The Status Register contains the specific die information such as density, device type, data bus width, refresh rate,

revision ID and manufacturers. The Status Register is only for READ. Below figure is Status Register Read Timing Diagram.

To read out the Status Register values, BA[1:0] set to 01b and A[12:0] set to all 0 with MRS command followed by

Read command with that BA[1:0] are Don’t care and A[12:0] set to all 0.

Is this supported in the SDRC?

Thanks,

--Gunter

over 12 years ago

0 Biser Gatchev-XID over 12 years ago

TI__Guru**** 393215 points

Hi Gunter,

I don't believe this is supported by the AM37X SDRC. There is a register (SDRC_MANUAL_p) for sending manual commands, but it only supports a limited set of command codes. Furthermore, all SDRC parameters have to be set manually, as described in the wiki (http://processors.wiki.ti.com/index.php/Setting_up_AM37x_SDRC_registers).

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

TI__Genius 14362 points

Hi Biser,

can we confirm whether there is a manual way of doing this with the command codes available, or do we already know that it is not possible?

Thanks

--Gunter

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

TI__Guru**** 393215 points

Hi Gunter,

I don't think there is any way that this can be implemented. Reading the status register requires a LOAD MODE REGISTER command with BA[1:0] = 01 and all address pins set to 0. The LOAD MODE REGISTER command is executed only implicitly by the SDRC and only with BA[1:0] = 00 or 10.

Processors

Processors forum

AM37xx SDRAM status register read