AM3352: GPMC DMA transfer

Raja Koteswara Rao

Part Number: AM3352

Hi,

Does am335x contains DMA which is capable of doing memory to memory transfers? If available does it work with 16 bit NOR type Single access asynchronous memory device (GPMC) i.e RAM to gpmc memory or vice versa ?

Regards

Raja

over 7 years ago

0 Biser Gatchev-XID over 7 years ago

TI__Guru**** 393215 points

Hi,

The AM335x GPMC has one DMA request to EDMA (GPMCEVT). It's used for NAND data accesses. You can however set up the EDMA for NOR flash accesses. See these threads for more information:
e2e.ti.com/.../409933
e2e.ti.com/.../552280
e2e.ti.com/.../284305

0 Raja Koteswara Rao over 7 years ago in reply to Biser Gatchev-XID

Intellectual 530 points

Hi,
Those threads doesn’t describe about memory to memory transfer. Does am335x support memory to memory transfer using DMA i.e RAM to RAM, RAM to GPMC(NOR type memory), GPMC to RAM etc?

Regards
Raja

0 RonB over 7 years ago in reply to Raja Koteswara Rao

TI__Mastermind 30526 points

Raja,

GPMC is considered a peripheral, so transfers to it are not really considered memory to memory, even if there is a memory attached. As Biser mentioned, our NAND and other drivers often use DMA when it makes sense and they can be a good reference.

Please see these two posts for using DMA for RAM to RAM via an example called DMA test.

e2e.ti.com/.../689540
e2e.ti.com/.../607788

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AM3352: GPMC DMA transfer