OMAP-L137 EMIFB - getting most memory space

HarriSiirtola

Other Parts Discussed in Thread: OMAP-L137

Hi,

I'm designing a custom OMAP-L137 board and need as much SDRAM as possible. I'd like to hear some suggestions for proper SDRAM chips.

I'm building my software with DSP/BIOS so if there are some matters to be considered on the hardware, please let me know.

Thanks,

Harri Siirtola/Tech Research Centre of Finland

over 15 years ago

0 Mariana over 15 years ago

TI__Mastermind 24340 points

Hi Harri,

The EVM schematics are available at:

http://support.spectrumdigital.com/boards/evmomapl137/

The EVM uses the IS42S16160B-6BL

Also, please see the document:

TMS320C674x/OMAP-L1x Processor External Memory Interface B (EMIFB) User's Guide

0 HarriSiirtola over 15 years ago in reply to Mariana

Intellectual 925 points

Hi Mariana,

Thanks for your quick reply! I forgot to mention that I have the EVM and its schematics. I also read the EMIFB UG but I'm a bit confused about the memory size representations. The OMAP-L137 datasheet states for EMIF B:

32-Bit or 16-Bit SDRAM With 256MB Address Space

The chips used in the EVM are only 16M x 16bit which is 256Mb (lowercase b means 'bit'). So is the uppercase 'B' a typo in the datasheet or is there a way of increasing the amount of SDRAM compared to the EVM solution? For example, does OMAP-L137 have additional chip select lines or some other way of increasing the memory chip count? I haven't had time to dig into the EMIF guide deep enough to find out.

Best Regards,

Harri

0 Mariana over 15 years ago in reply to HarriSiirtola

TI__Mastermind 24340 points

Hi Harri,

Let me explain a little better.

256 MB is the address space for EMIFB. But that does not mean necessarily that the EMIF interface supports it all.

The actual max size of SDRAM you can put on it is:

16/32-bit SDRAM, up to 512 Mbit (EMIFB) - please see page 13 of the TMS320C674x/OMAP-L1x Processor External Memory Interface B (EMIFB) User's Guide for an example configuration.

16-bit SDRAM, up to 128 Mbit (EMIFA)

Let me know if you have more questions.

0 HarriSiirtola over 15 years ago in reply to Mariana

Intellectual 925 points

Ok, thanks for the clarifying answer. Just to make this absolutely sure: using two IS42S16320B chips (which are double the size of the ones in the EVM) gives the maximum possible SDRAM using the configuration on guide page 13. The two SDRAM chip versions have exactly the same hw pins according to the datasheets.

I only have EMIF B to use with RAM, that's why I'm talking about 'maximum'.

Harri

0 Mariana over 15 years ago in reply to HarriSiirtola

TI__Mastermind 24340 points

HarriSiirtola said:
Just to make this absolutely sure: using two IS42S16320B chips (which are double the size of the ones in the EVM) gives the maximum possible SDRAM using the configuration on guide page 13.

Yes. On OMAP-L137 you can go up to 128 MBytes SDRAM on EMIFB, and that is what you are doing with the 2 memories.

Processors

Processors forum

OMAP-L137 EMIFB - getting most memory space