AM335X EDMA

xing lui

Hi,

I know that the source address and the dest address should be programmed as 256-bit aligned in constant addressing mode of EMDA3.But our ethernet device works that using GPMC,and its data IO address is 0x1C000004.
How to progam the EDMA channel parameters if we want to read/write data via EDMA3?

over 10 years ago

0 Biser Gatchev-XID over 10 years ago

TI__Guru**** 393215 points

Hi,

You should check section 11.3.19.4 "Peripheral Servicing Example" in the AM335X TRM Rev. K.

0 Wolfgang Muees1 over 10 years ago in reply to Biser Gatchev-XID

Genius 3685 points

If you want to do EDMA via GPMC, you should read this:

http://e2e.ti.com/support/arm/sitara_arm/f/791/t/348712.aspx

regards

Wolfgang

0 xing lui over 10 years ago in reply to Biser Gatchev-XID

Intellectual 990 points

Hi,Biser

I think you misunderstand my question.I just want to avoid the address limit of 256-bit aligned,because our device data IO address is 0x1C000004.

the section 11.3.3.2.2 "Channel Source Address (SRC)" describes this rule.

0 xing lui over 10 years ago in reply to Wolfgang Muees1

Intellectual 990 points

hi,Wolfgang

thanks a lot for your info.

0 xing lui over 10 years ago in reply to Biser Gatchev-XID

Intellectual 990 points

hi,

as wolfgang's descriprion,"For some reason it comes with an annoying 32-byte alignment restriction on the address of the FIFO, which rather limits its usefulness." why am335x's EDMA has this limitation?Does TI has any suggestions for this case?

0 Wolfgang Muees1 over 10 years ago in reply to xing lui

Genius 3685 points

DO NOT use FIFO mode!

Use normal address increment mode!

Emulate constant address mode by choosing the right parameters for the address increment registers.

0 xing lui over 10 years ago in reply to Wolfgang Muees1

Intellectual 990 points

hi,Wolfgang.

thanks very much! I will review the EDMA section about the Increment mode.

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