Re: How can DMA help CPU to do other useful work when DMA is accessing memory?

["Mouhammad Tayseer Alquoatli" <idoit.ief@xxxxxxxxx>]

On 8/7/06, Chandrashekar MC <mc.chandrashekar@xxxxxxxxx> wrote:

This is a basic question,

As we know CPU sets the DMA registers and give the control of RAM to DMA for datatransfer.

When DMA is transferring data between RAM and Device, CPU can not access RAM. Without access to RAM(which has executalble code), how can CPU do any useful work during DMA datatransfer?

CPU can analyze/execute instructions on it's local registers while the DMA is accessing memory

I have a second question, Is it that only devices connected to ISA buses can use DMA?

 

Regards,

Chandra

-- 
Mouhammad Tayseer Alquoatli