Post by thread:[OT] Hardware access under Linux

Scott Newell wrote: > Does anyone have any good links or pointers to this kind of low-level > device access? Yes, sure. Fetch picprg2.2 from http://www.tatoosh.com/nexus/picpgmr.shtml for a simple example of low-level access to the printer port under Linux. See the file lowlvl.c within the package. No assembly code required. I have adapted this code for my own use to program 12C509 chips. -- James Cameron (spam_OUTcameronTakeThisOuTstl.dec.com) OpenVMS, Linux, Firewalls, Software Engineering, CGI, HTTP, X, C, FORTH, COBOL, BASIC, DCL, csh, bash, ksh, sh, Electronics, Microcontrollers, Disability Engineering, Netrek, Bicycles, Pedant, Farming, Home Control, Remote Area Power, Greek Scholar, Tenor Vocalist, Church Sound, Husband. "Specialisation is for insects." -- Robert Heinlein.

On Tue, Jan 19, 1999 at 03:59:11PM -0600, Scott Newell wrote: > Every once in a while, people discuss building PIC programmers or other > hardware for use under Linux. Now that I've got a Linux machine built up, > I'm interested in using the PC's serial and parallel ports to interface to > various devices, including some PIC projects. > > Does anyone have any good links or pointers to this kind of low-level > device access? (I'm comfortable with C++, and I really don't want to deal > with the backwards AT&T-style x86 assembler syntax.) Two good books that cover this topic are: Linux Device Drivers by Alessandro Rubini (O'Reilly) www.amazon.com/exec/obidos/ASIN/1565922921/qid%3D916832697/002-1508759-93 54633 and Linux Kernel Internals 2/E, Edited by Michael Beck (Addison-Wesley) www.amazon.com/exec/obidos/ASIN/0201331438/ref=sim_books/002-1508759-9354 633 In addition, the book Programming the Parallel Port; Interfacing the PC for Data Acquisition and Process Control by Dhananjay V. Gadre (R&D Books) www.amazon.com/exec/obidos/ASIN/0879305134/qid=916833059/sr=1-2/002-15087 59-9354633 while mostly DOS-oriented, does have one chapter on writing a Linux device driver for a parallel-port DAQ application (beware, though, I found that this book uses really funky jargon and diagrammatic conventions, and is rife with typos. Still, if you can get past that, there's a lot to learn from it). Most of what goes on at that level is typically done in ANSI C, rather than C++. --Bob -- ============================================================ Bob Drzyzgula It's not a problem .....bobKILLspam@spam@drzyzgula.org until something bad happens ============================================================

{Quote hidden}> > On Tue, Jan 19, 1999 at 03:59:11PM -0600, Scott Newell wrote: > > Every once in a while, people discuss building PIC programmers or other > > hardware for use under Linux. Now that I've got a Linux machine built up, > > I'm interested in using the PC's serial and parallel ports to interface to > > various devices, including some PIC projects. > > > > Does anyone have any good links or pointers to this kind of low-level > > device access? (I'm comfortable with C++, and I really don't want to deal > > with the backwards AT&T-style x86 assembler syntax.) > > Two good books that cover this topic are: > > Linux Device Drivers by Alessandro Rubini (O'Reilly) > > and > > Linux Kernel Internals 2/E, Edited by Michael Beck (Addison-Wesley) > > In addition, the book > > Programming the Parallel Port; Interfacing the PC for Data > Acquisition and Process Control by Dhananjay V. Gadre (R&D Books) > www.amazon.com/exec/obidos/ASIN/0879305134/qid=916833059/sr=1-2/002-150 8759-9354633 {Quote hidden}> > while mostly DOS-oriented, does have one chapter on > writing a Linux device driver for a parallel-port DAQ > application (beware, though, I found that this book > uses really funky jargon and diagrammatic conventions, > and is rife with typos. Still, if you can get past that, > there's a lot to learn from it). > > Most of what goes on at that level is typically > done in ANSI C, rather than C++. Bob, I'm thinking that the device driver level is a bit too far under the surface for what Scott wants to do. Both parallel and serial interfaces are accessible from the user level, the parallel port via the port interface, the serial ports via the already excellent serial driver. The Linux IO-Port programming Mini-Howto has more than enough information to get started. It can be found at: http://metalab.unc.edu/LDP/HOWTO/mini/IO-Port-Programming.html As another poster pointed out the low level interface code for the Linux based picprg by Brian Lane of Nexus computing: http://www.tatoosh.com/nexus/picpgmr.shtml is quite instructive. For the most part a Linux driver is required under one of three conditions: 1) Interrupts are involved. 2) Timing is critical. 3) Access must be managed to multiple simultaneous users/applications For simple stuff to the parallel port just use the user level I/O interface and make the application setuid root (because I/O require root access). BTW it may bear repeating (I haven't seen a Linux based environment discussion lately) that a Linux based PIC environment is doable. Last semester I had one of my students build a parallel port based 16[CF]84 programmer that uses Nexus Computers picprog to program, Timo Rossi's picasm located: http://www.iki.fi/trossi/pic/ for an assembler, and I experimented with Scott Dattalo's gpsim simulator at: http://interstice.com/~sdattalo/gnupic/gpsim.html Which works really well but I think need in addition to the complicated node and waveform based pin simlation a really simple interface where you can just set a pin high or low for input. I banged out two quick light control projects over the holidays with this setup and was extremely happy to finally retire my PICSTART/DOSEMU based system that I was using earlier. Next on my project list is adding a second 16C84 based programmer with a serial interface which will program the rest of the PIC family. I'm looking forward to hearing more about PIC and Linux integration here on the list. BAJ

I ran across this the other day. I haven't been able to download it though. http://reality.sgi.com/jamesb/gpasm/ Erik Byron A Jeff wrote: {Quote hidden}> > > > > On Tue, Jan 19, 1999 at 03:59:11PM -0600, Scott Newell wrote: > > > Every once in a while, people discuss building PIC programmers or other > > > hardware for use under Linux. Now that I've got a Linux machine built up, > > > I'm interested in using the PC's serial and parallel ports to interface to > > > various devices, including some PIC projects. > > > > > > Does anyone have any good links or pointers to this kind of low-level > > > device access? (I'm comfortable with C++, and I really don't want to deal > > > with the backwards AT&T-style x86 assembler syntax.) > > > > Two good books that cover this topic are: > > > > Linux Device Drivers by Alessandro Rubini (O'Reilly) > > > > and > > > > Linux Kernel Internals 2/E, Edited by Michael Beck (Addison-Wesley) > > > > In addition, the book > > > > Programming the Parallel Port; Interfacing the PC for Data > > Acquisition and Process Control by Dhananjay V. Gadre (R&D Books) > > www.amazon.com/exec/obidos/ASIN/0879305134/qid=916833059/sr=1-2/002-1 508759-9354633 {Quote hidden}> > > > while mostly DOS-oriented, does have one chapter on > > writing a Linux device driver for a parallel-port DAQ > > application (beware, though, I found that this book > > uses really funky jargon and diagrammatic conventions, > > and is rife with typos. Still, if you can get past that, > > there's a lot to learn from it). > > > > Most of what goes on at that level is typically > > done in ANSI C, rather than C++. > > Bob, > > I'm thinking that the device driver level is a bit too far under the surface > for what Scott wants to do. Both parallel and serial interfaces are accessible > from the user level, the parallel port via the port interface, the serial > ports via the already excellent serial driver. > > The Linux IO-Port programming Mini-Howto has more than enough information to > get started. It can be found at: > > http://metalab.unc.edu/LDP/HOWTO/mini/IO-Port-Programming.html > > As another poster pointed out the low level interface code for the Linux > based picprg by Brian Lane of Nexus computing: > > http://www.tatoosh.com/nexus/picpgmr.shtml > > is quite instructive. > > For the most part a Linux driver is required under one of three conditions: > > 1) Interrupts are involved. > 2) Timing is critical. > 3) Access must be managed to multiple simultaneous users/applications > > For simple stuff to the parallel port just use the user level I/O interface > and make the application setuid root (because I/O require root access). > > BTW it may bear repeating (I haven't seen a Linux based environment discussion > lately) that a Linux based PIC environment is doable. Last semester I had one > of my students build a parallel port based 16[CF]84 programmer that uses > Nexus Computers picprog to program, Timo Rossi's picasm located: > > http://www.iki.fi/trossi/pic/ > > for an assembler, and I experimented with Scott Dattalo's gpsim simulator at: > > http://interstice.com/~sdattalo/gnupic/gpsim.html > > Which works really well but I think need in addition to the complicated node > and waveform based pin simlation a really simple interface where you can just > set a pin high or low for input. > > I banged out two quick light control projects over the holidays with this > setup and was extremely happy to finally retire my PICSTART/DOSEMU based > system that I was using earlier. > > Next on my project list is adding a second 16C84 based programmer with a > serial interface which will program the rest of the PIC family. > > I'm looking forward to hearing more about PIC and Linux integration here on > the list. > > BAJ

with respect to parallel port Linux drivers, On Wed, 20 Jan 1999, Byron A Jeff wrote: > For simple stuff to the parallel port just use the user level I/O interface > and make the application setuid root (because I/O require root access). True. In fact, The person working on hacking the PicStart+ protocol has been successful capturing the data flowing on the serial line between a PC (running windows) and the programmer. Then he could cat that data from Linux directly to the Picstart+ and get the programmer to respond! All of this without writing any special drivers or even needing an oscilloscope. > BTW it may bear repeating (I haven't seen a Linux based environment discussion > lately) that a Linux based PIC environment is doable. Last semester I had one That's because most of the Linux based pic development discussion has moved to the gnupic mailing list. Here lately though, the only traffic has pretty much been gpsim release announcements. > of my students build a parallel port based 16[CF]84 programmer that uses > Nexus Computers picprog to program, Timo Rossi's picasm located: > http://www.iki.fi/trossi/pic/ That is a very nice assembler. However, I would recommend gpasm instead since it accepts mpasm formatted source files without modification: http://reality.sgi.com/jamesb/gpasm/ > for an assembler, and I experimented with Scott Dattalo's gpsim simulator at: > > http://interstice.com/~sdattalo/gnupic/gpsim.html > > Which works really well but I think need in addition to the complicated node > and waveform based pin simlation a really simple interface where you can just > set a pin high or low for input. The stimulation interface is way too complicated.... I will be addressing this issue shortly. In the mean time however, I've begun hacking gpasm to provide symbolic information that may be used by gpsim. In the next release I expect to add commands that will allow one to view source and list files and set breakpoints symbolically. Incidentally, I've also begun devoping a gui based register viewer. I probably will not have that available in the next gpsim release though. > I banged out two quick light control projects over the holidays with this > setup and was extremely happy to finally retire my PICSTART/DOSEMU based > system that I was using earlier. > > Next on my project list is adding a second 16C84 based programmer with a > serial interface which will program the rest of the PIC family. Great! I'll be looking forward to that! > I'm looking forward to hearing more about PIC and Linux integration here on > the list. Me too. However, many of us prefer to have the detailed discussions on the GNUPIC mailing list. Go to the gnupic webpage on info how to subscribe. http://reality.sgi.com/jamesb/gnupic/ (The traffic is 2.5 orders of magnitude lower) Scott