A POST (power on self test) card is basically a dumb card that decodes an I/O port (80h) and displays the value. Nothing but the CPU access to the ROM and I/O bus (PCI or ISA) has to work to access the card.
mov al, CRUMB_1 out 80h,al
Like I said really down and dirty. But sometimes that's the only way to debug a system.
I snagged a link to some sources from a message posted here a couple of days ago.
Jordan
At 10:54 AM 5/15/2003 -0700, Frank wrote:
I don't mind getting dirty. as a matter of fact i prefer to work in the dirt. That's why I'm looking at linuxbios.:-) I come from a ppc and mips world where debuuger's are a lot more plentiful and cheaper. What is a "POST card"... --- jarcher jarcher@pobox.com wrote:
To add to Ron's message.
It varies a lot with your experience and how dirty you want to get.
A simple POST card and a lot of creative POST code bread crumbs is the cheap and dirty way to go, until you get the serial port debugger up and running. But it requires you to be really creative in crawling through the code. And takes a lot of time.
But you can move up the a logic analyzer looking at bus cycles or an ICE (in circuit emulator) looking at CPU activity These two are expensive (lots of $10K), but you can often rent them. Setup is usually the time burner here. But with a LA you can take selective pictures of events chained together in time. I don't know if SIS has an ICE for their SOC products.
Jordan
PS: Has anyone done a USB interface low level debugger? Early BIOS or at least just prior to payload decompress.
At 12:00 PM 5/15/2003 -0400, you wrote:
Message: 10 Date: Thu, 15 May 2003 08:50:44 -0700 (PDT) From: Frank frannk_m1@yahoo.com Subject: Re: debugger To: ron minnich rminnich@lanl.gov Cc: linuxbios@clustermatic.org
sis55x SOC x86 based --- ron minnich rminnich@lanl.gov wrote:
On Thu, 15 May 2003, Frank wrote:
Can anyone recommend a debugger for bringing up
LinuxBios on
an
x86 system...
what kind of chip? and how much money can you spend?
ron
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