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Re: ISA BUS Master
- To: Mailing List Recipients <firstname.lastname@example.org>
- Subject: Re: ISA BUS Master
- From: "John R Pierce" <email@example.com>
- Date: Fri, 5 Mar 1999 22:31:15 -0800
- Delivered-To: pcisig@teleport.COM
- References: <7CHKjZof1CB@andiport.ius>
- Resent-Date: Fri, 5 Mar 1999 23:07:37 -0800
- Resent-From: firstname.lastname@example.org
- Resent-Message-ID: <"8z78k.0.Pa7.7oCus"@electra.znyx.com>
- Resent-Sender: email@example.com
> I want to build a ISA card witch has to read 8 Kbyte from the Video Text
> Memory. This Card should be run under any PCI Boards with an ISA Bridge.
> Does every ISA Bridge Support "ISA BUS MASTER " ?
> When my Cards became a Bus Master, must i take over the Refresh Signal
> every 15 Ás , or is this Signal on the ISA-BUS is only a relict from the
> former 128Kbyte RAM Card`s in the 80th s ?
all ISA busses by definition support ISA dma which includes ISA bus mastering.
I'd not plan on holding the ISA bus for an entire 8K transfer however! Do
about 8-16 xfers in a burst, release the bus and rearbitrate it. that will
alleviate you from worrying about refresh or anything else, as well as
forstalling any interrupt latency issues.