hi i am new to OS.. and would like to know if the area for Direct memory access in the Main memory is fixed.
thank you
DMA
-
Pype.Clicker
- Member
- Posts: 5964
- Joined: Wed Oct 18, 2006 2:31 am
- Location: In a galaxy, far, far away
- Contact:
Re:DMA
well, DMA controller can be programmed to access any page of 64KB within the lowest 16MB of your physical memory. you select it by properly setting the 'base register" and the "page register" for the DMA channel you want to use.
we have more talks about DMA here, if you want to get a look
so if 'fixed' mean 'at which address should i expect DMA to read/write', then no it's not fixed, though due to alignment/range limitations, most drivers tend to always use the same (or a few) buffers for DMA transfers and then memcpy the data where it's supposed to go.
we have more talks about DMA here, if you want to get a look
so if 'fixed' mean 'at which address should i expect DMA to read/write', then no it's not fixed, though due to alignment/range limitations, most drivers tend to always use the same (or a few) buffers for DMA transfers and then memcpy the data where it's supposed to go.