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Re: What hardware do I need to test the i386 system?


>>>>> "Jerry" == Jerry Beckmann <jbeckmann_1999@yahoo.com> writes:

    Jerry> I am running an AMD SC400 processor on a eval board that
    Jerry> doesn't have a BIOS or an OS that is supporting the serial
    Jerry> port. I can write a bootloader program that sets up things
    Jerry> like the serial port, but I need to know what all the test
    Jerry> programs need and what type of polling or interrupt routine
    Jerry> I need to write to get the data into the RAM. Are we
    Jerry> talking a straight byte to byte transfer or is there some
    Jerry> kind of compress algorithm being used in the transfer?

    Jerry> If it matters at all, I will be booting off of a PC Card
    Jerry> that is acting like a ROM device. I am willing to help the
    Jerry> development process for a bootable ROM once I get something
    Jerry> to show the upper management folk.

The normal approach for an embedded board is to implement and install
a set of gdb stubs in the EPROM/flash/whatever. The gdb stubs will
then support downloading the application (including eCos test
executables) into RAM via serial line, and debugging it.

For the existing x86 PC port, instead of installing the gdb stubs
image in EPROM/flash it is written to a floppy and then the normal PC
boot mechanisms can be used. The application is then downloaded over
a serial line from another machine. For your requirements the more
conventional EPROM/flash approach seems a better match. As far as I
know this has not yet been implemented for any x86 platform.

More information on gdb stubs etc. can be found in the eCos reference
manual, http://sourceware.cygnus.com/ecos/docs-1.3.1/, which includes
a porting guide.

    Jerry> That reminds me, I haven't seen anything in terms of a
    Jerry> X Windows or other GUI. Is there one for eCos, or are
    Jerry> you just porting over the XFree86 (or other smaller
    Jerry> GUI) for people who need it?

X is not appropriate for most embedded systems, it is just too big.
Also, a typical X installation involves at least two processes, the
server and the client, which does not map well on to eCos. There are
other graphics libraries, e.g. NanoGUI
(http://www.linuxhacker.org/nanogui/), which might be more
appropriate. An important issue here is the kind of display you are
targetting - TV, large LCD, small LCD, ... - since something suitable
for a small LCD might look rather poor on a larger display.

So far there has not been a contributed port of NanoGUI or anything
similar, and none of the customers paying Red Hat for a supported eCos
port have specified a GUI library as a requirement.

Bart Veer // eCos net maintainer

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