TMS320F28377S: Use of 2Mx16 async ram

Andrea Rossi28

Part Number: TMS320F28377S

I would use 28377S to interface external 16-bit ASRAM up to 2Mx16. I tried to use Pin-Mux Tool and reading the technical reference manual, but I have the doubt about addressing space of ASRAM and if DQM byte enable is needed or not.

Using PinMux for 28377S package 176 PTP, if I enable DQM pins the maximum address bit is "A14" because "A15-A16-A17-A18" are blocked by "DQM[3-0]" pins.

This is a problem for me because I would reuse the same architecture of another project with F28335 with external 16-bit ASRAM that allow me to address up to "A18" bit address.

Please, can you clarify it and if I can use 28377S to manage up to 2Mx16 of ASRAM addressing space? How to configure pin Mux to have these resources?

over 6 years ago

0 tlee over 6 years ago

TI__Guru 62975 points

Andrea,

You should be able to tie the Byte-Enable signals low at ASRAM since the memory accesses will always be 16b words. You can then use the DQM pins as address signals.

-Tommy

0 Andrea Rossi28 over 6 years ago in reply to tlee

Prodigy 110 points

Thanks for the answer.
Another question: if I would use 1Mx32 ASRAM I needs 2 write enable (as used on F28335) . How can I manage the full access to 1Mx32 bit memory?

0 Vivek Singh over 6 years ago in reply to Andrea Rossi28

TI__Guru** 109165 points

Hi,

If you are using 32bit ASRAM then you have to use DQM1 and DQM2 (or DQM3) hence address range is restricted to A0 to A15.

Also there is pending correction for this documentation in next release - "The max addressable range is 2MB (not 2M x 16) if using 16bit memory".

Regards,
Vivek Singh

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TMS320F28377S: Use of 2Mx16 async ram