Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!nrl-cmf!mailrus!tut.cis.ohio-state.edu!erd From: erd@tut.cis.ohio-state.edu (Ethan R. Dicks) Newsgroups: comp.sys.amiga.tech Subject: Information requested to construct extra serial ports (kinda long) Keywords: more ports newserial.device HELP! Message-ID: <29527@tut.cis.ohio-state.edu> Date: 14 Dec 88 06:48:55 GMT Organization: The Ohio State University Dept of Computer and Information Science Lines: 51 [ I wonder if the grue is a cousin to the line ea... ] From all the pleas on the 'net lately, I am considering picking up my long delayed project of working on a serial port expansion thing. I lack sufficient information on writing the device driver. The last time I picked up this project, I was stalled waiting for the mapper.device stuff to be finalized. I have decided to forge ahead and create an incompatible serial expander, mostly because it won't autoconfig, and thus, must be MOUNTed... The hardware is simple... plug a $20 PC/XT (or ESA, if you prefer) Serial card from JameCo (with or without the $10 extra port option) into any PC/XT bus adapter, such as the WEDGE. This gives you the UART registers sitting in a known place in memory. The device driver is where I am a little confused. I can easily write the register twiddling, it is the DOS interface and overall design which confuses me... 1) What is the difference between a handler (as in port-handler) and a device (as in serial.device)? Which one (or both) will I want to write, to add the new device names COM1:, COM2: ...? 2) Can I use Matt Dillon's generic DOS device, or must I wade through the RKM to pluck all the information myself? I guess that question 1 is the more important. I see little distinction right now, but I surmise that there _must_ be some distinction, or there would not be both types. If I can get a skeletal structure, and a list of the DOS packet type that a serial port must accept (that _should_ be in the RKM), I can probably get a working driver banged out over Christmas break. Am I missing something? I am assuming that I will pass the address of the UART registers to the device driver via the MASK MountList entry. Is this a no-no? Is there a better way to do this? All the driver should need is the understanding designed in about the UART, and a base address of the registers, passed at MOUNT time, and the MASK entry seems the easiest way to pass a longword. The sooner I get some information, the faster I can get this done and into the world. Thanks in advance, -ethan -- Ethan R. Dicks | ###### This signifies that the poster is a member in Software Results Corp| ## good sitting of Inertia House: Bodies at rest. 2887 Silver Drive | ## Columbus OH 43211 | ###### "You get it, you're closer.