Hands on PCI interface ...
in [Embedded]
|
Next: at89c52 bootloader
From: Jonathan Kirwan on 4 Feb 2005 14:58 On Fri, 04 Feb 2005 16:25:30 GMT, nico(a)puntnl.niks (Nico Coesel) wrote: >I think it is possible if the ISA card can use 1 interrupt or share >interrupts. You'll need some intelligence to convert ISA DMA to PCI >bus mastering (which is more or less the same, only the addresses are >generated at a different spot). The problem isn't that, it's the timing requirements of ISA DMA. They simply cannot be met by the PCI bus using normal PCI transactions. This is part of why the sideband signals are required to the main chipset, so that the chipset can be informed about the non-standard nature of certain transactions. Without them, the DMA timing itself cannot be supported on the PCI. >The amount of I/O and memory addresses >can be preset on the PCI card so substractive addressing isn't needed. I suppose that's possible, of course. Usually, ISA bus transactions are handled as subtractive decoding, though. Jon
From: Keith Williams on 4 Feb 2005 15:20 In article <ink701dhanogqu5kvljdad31qr36s2fil6(a)4ax.com>, jkirwan(a)easystreet.com says... > On Fri, 4 Feb 2005 09:53:19 -0500, Keith Williams <krw(a)att.bizzzz> wrote: > > >> The southbridge or PCI-ISA bridge chip can only exist with "side-band" channels > >> to the main chipset. > > > >No side-band channels/signals are needed. > > Why do you say this? It's certainly been true for as long as I've worked on > these chipsets. That does date back to the P2, but have things changed? I > doubt it. No sideband signals are in the PCI spec (they wouldn't be "sideband" ;-). Certainly the southbridge and subtractive decoding are covered. -- Keith
From: aiiadict on 4 Feb 2005 15:25 How about this? A modern PC motherboard with ISA slots? I am looking for the fastest processor speed available. Rich
From: Nico Coesel on 4 Feb 2005 16:15 Jonathan Kirwan <jkirwan(a)easystreet.com> wrote: >On Fri, 04 Feb 2005 16:25:30 GMT, nico(a)puntnl.niks (Nico Coesel) wrote: > >>I think it is possible if the ISA card can use 1 interrupt or share >>interrupts. You'll need some intelligence to convert ISA DMA to PCI >>bus mastering (which is more or less the same, only the addresses are >>generated at a different spot). > >The problem isn't that, it's the timing requirements of ISA DMA. They simply >cannot be met by the PCI bus using normal PCI transactions. This is part of why >the sideband signals are required to the main chipset, so that the chipset can >be informed about the non-standard nature of certain transactions. Without >them, the DMA timing itself cannot be supported on the PCI. I'm convinced it can be done with a trick: have the PCI-ISA bridge read data from the ISA card first, store this and then send it to the main memory. This way you separate the timing between the ISA and PCI bus. This also allows for a smarter scheme in which more data is buffered in the PCI bridge before it is send to the main memory. You'll need to have the PCI bridge generate the addresses anyway. Needless to say, you'll need to change the ISA driver software into a PCI version as well. -- Reply to nico(a)nctdevpuntnl (punt=.) Bedrijven en winkels vindt U op www.adresboekje.nl
From: Rich Grise on 4 Feb 2005 18:01
On Fri, 04 Feb 2005 12:25:07 -0800, aiiadict wrote: > How about this? > > A modern PC motherboard with ISA slots? > I am looking for the fastest processor speed > available. > How about this? http://www.google.com/search?q=isa+bus+motherboard Cheers! Rich |