Message-ID: <357BCC3A.E330B9D@post.comstar.ru> Date: Mon, 08 Jun 1998 15:34:18 +0400 From: Dim Zegebart Reply-To: zager AT post DOT comstar DOT ru Organization: Comstar Ltd. MIME-Version: 1.0 To: Javier Calleja CC: djgpp AT delorie DOT com Subject: Re: Questions about interrupt handler and bus AT References: <01bd92b7$fc621a00$0100a8c0 AT dismuntel DOT ctv DOT es> Content-Type: text/plain; charset=koi8-r Content-Transfer-Encoding: 7bit Precedence: bulk Javier Calleja wrote: > 2 Could someone give me the AT bus protocol ot tell me where I can find > it? I need communicate the PC with a ISA card which have a 386 micro, I have > to build a communication protocol via AT bus, how can I do it? > AFAIK, there are several possible ways which you may use to communicate with ISA device : 1. using port I/O 2. using DMA chanel 3. using mapped shared memory For example comm card with UART use first method and Gravis Ultra Sound card using all three. So, you should obtain documentation from manufacturer of your card to know how exactly you can interface with device. AT bas is totaly hidden from software which runs on CPU, it means you can't catch any ISA signals (exept some special cases) from within djgpp programm. All this low level stuff performed by 'micro' programm which runs on micro-controller(s) chip which operate entire ISA device. On the over hand, if you need to develop ISA device you should definetely visit bookstore and buy several books about ISA bus. I'm sure you can find ISA specification somethere on Net, but IMHO you need more explanating description on how to design a real device not just 'pin-means-what' and 'signal-means-what' paper. PS. My answer is just a common words, so ask more exact question obout what is your _TASK_ to get more precise answer. -- ____ ____ | \ / Dim Zegebart ____/____ Moscow Russia WWW - http://www.geocities.com/siliconvalley/pines/7817 DZcomm - comm library for Allegro Palantir - multitasking kernel for Allegro (based on PDMLWP)