DMA to GPIO

Ed Hillen

I am considering a 2806 (Piccolo) in an application where I have 2 sets of 8 LEDs muxed (on one set of 8 GPOuts). I would like to use DMA to write the first set of values then (to other bank) a second set of values. I would like to setup the two sets of 8 bits (in a BYTE) in SRAM and have DMA (on timer) move first byte to GPIO port, then index SRAM) and send second byte out to GPIO port. Can this be done? It is not obvious to me that the GPIO register can be the destination of a DMA transfer.

over 15 years ago

0 David Foley over 15 years ago

TI__Expert 8500 points

Ed,

Sorry, the DMA bus does not connect to the GPIO registers.

Regards,
Dave Foley

0 Ed Hillen over 15 years ago in reply to David Foley

Prodigy 200 points

Thanks Dave,

I'm also considering a Stellaris 5xxxx or 9xxxx part. Can you tel me if this is possible with their DMA?

Thx

0 David Foley over 15 years ago in reply to Ed Hillen

TI__Expert 8500 points

Ed,

I apologize. I don't know enough about the Stellaris parts to answer that one. Try posting the same question on the Stellaris Forum (http://e2e.ti.com/support/microcontrollers/stellaris_arm_cortex-m3_microcontroller/f/471.aspx). You'll probably get an answer faster than I could give you.

Regards,
Dave Foley

0 quark over 15 years ago

Expert 2220 points

For something as slow as LEDs on a timer, why bother with a DMA? An regular interrupt routine should be sufficient.

Is there any reason that you must use a DMA?

One idea may be to use the F28335 (or any chip with an external memory interface) and use DMA on that.

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DMA to GPIO