DMA TX buffers for MAC

[brberie]

Posted on November 25, 2012 at 02:41

Why application needs to copy ethernet frame to the TX buffer first and then DMA will move it to the MAC fifo? Why is it bad idea to set up DMA to read the frame directly from application? Just want to know the reason(s)

Thank you #ethernet-mac-dma-stm32f

[Tesla DeLorean]

Posted on November 25, 2012 at 03:51

Seem to recall the F4 can pull directly from the main 128K.

Reasons it might be moved are alignment, fragmentation, or reuse of the buffers it's originally built with. Or that it's a simpler to abstract the other layers if it's not tied to a specific hw implementation, or buffer management scheme. Try sending some 802.3 Ethernet frames directly.

[brberie]

Posted on November 25, 2012 at 04:10

I may. As of now just reading the manual(swearing continuously) and reading the code(no words to describe, just letters) and combining two together...I'd like to see professionally written driver but have to use what is available.