Hi, I just have another question about 1394 address? what is the relationship between 1394 adddress and memory address? --------------------------------------- Posted through http://www.EmbeddedRelated.com
1394 address and memory address.
Started by ●October 18, 2010
Reply by ●October 19, 20102010-10-19
On 10/18/2010 05:00 AM, huxuelei wrote:> Hi, I just have another question about 1394 address? > what is the relationship between 1394 adddress and memory address?Whatever the designer wants it to be. 1394 is _organized_ with an address space, but there's absolutely no requirement that there be any clear mapping between the 1394 address space and the address space of memory on the device -- or even that the device has memory to address. The 1394 product that I worked on treated the asynchronous packets as messages, and the addresses as tags. Any correspondence between "register addresses" in 1394 space and memory locations was random and could change with the next compile of the software, and in fact some of the responses were calculated on the fly when a query was received. So don't get too wrapped around the axle with the term "address space" in 1394. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" was written for you. See details at http://www.wescottdesign.com/actfes/actfes.html
Reply by ●October 19, 20102010-10-19
>On 10/18/2010 05:00 AM, huxuelei wrote: >> Hi, I just have another question about 1394 address? >> what is the relationship between 1394 adddress and memory address? > >Whatever the designer wants it to be. 1394 is _organized_ with an >address space, but there's absolutely no requirement that there be any >clear mapping between the 1394 address space and the address space of >memory on the device -- or even that the device has memory to address. > >The 1394 product that I worked on treated the asynchronous packets as >messages, and the addresses as tags. Any correspondence between >"register addresses" in 1394 space and memory locations was random and >could change with the next compile of the software, and in fact some of >the responses were calculated on the fly when a query was received. > >So don't get too wrapped around the axle with the term "address space" >in 1394. > >-- > >Tim Wescott >Wescott Design Services >http://www.wescottdesign.com > >Do you need to implement control loops in software? >"Applied Control Theory for Embedded Systems" was written for you. >See details at http://www.wescottdesign.com/actfes/actfes.html >My understanding as follow: In my 1394 system, I can use any address in the serial bus. after I received a write request, my system can decide the destination offset is valid or not. If the offset is valid, I can pick the data up in the write request, and copy them to anywhere in my host's memory. The whole serial bus address to memory policy is defined by myself. Is that right? --------------------------------------- Posted through http://www.EmbeddedRelated.com
Reply by ●October 20, 20102010-10-20
On 10/19/2010 07:53 PM, huxuelei wrote:>> On 10/18/2010 05:00 AM, huxuelei wrote: >>> Hi, I just have another question about 1394 address? >>> what is the relationship between 1394 adddress and memory address? >> >> Whatever the designer wants it to be. 1394 is _organized_ with an >> address space, but there's absolutely no requirement that there be any >> clear mapping between the 1394 address space and the address space of >> memory on the device -- or even that the device has memory to address. >> >> The 1394 product that I worked on treated the asynchronous packets as >> messages, and the addresses as tags. Any correspondence between >> "register addresses" in 1394 space and memory locations was random and >> could change with the next compile of the software, and in fact some of >> the responses were calculated on the fly when a query was received. >> >> So don't get too wrapped around the axle with the term "address space" >> in 1394. >> >> -- >> >> Tim Wescott >> Wescott Design Services >> http://www.wescottdesign.com >> >> Do you need to implement control loops in software? >> "Applied Control Theory for Embedded Systems" was written for you. >> See details at http://www.wescottdesign.com/actfes/actfes.html >> > > My understanding as follow: > In my 1394 system, I can use any address in the serial bus. > after I received a write request, my system can decide the destination > offset is valid or not. If the offset is valid, I can pick the data up in > the write request, and copy them to anywhere in my host's memory. > The whole serial bus address to memory policy is defined by myself. > Is that right? >Right. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" was written for you. See details at http://www.wescottdesign.com/actfes/actfes.html
