[coreboot] Debugging techniques for GeodeLX-based platforms

Jordan Crouse jordan.crouse at amd.com
Mon Apr 21 18:28:37 CEST 2008


On 21/04/08 15:17 +0200, llandre wrote:
> Hi all,
> 
> I'm going to start my first Geode-based project. I was googling around 
> to understand which debugging techniques are available for this processor.
> So far I found:
> * (old fashioned) burn boot flash and see what happens (flash 
> programming can be performed with external programmer or via JTAG)
> * ROM emulator (see for example 
> http://wiki.laptop.org/go/ROM_Emulators_for_OLPC or 
> http://www.tech-tools.com/er3.htm)
> 
> I'm wondering if it is possible to avoid the long burn-debug-recode cycle.
> For example, in case JTAG debugger is available, I should be possible to 
> download the boot code in RAM (on-chip or external) and execute it under 
> debugger control (I often used this technique in ARM/PowerPC-based 
> embedded systems).
> I was having a look at Geode LX databook and I found that the GeodeLink 
> Control Processor provides 1KB SRAM that could be suitable for this 
> purpose. Anybody implemented such solution?
> Any comment or advice will be appreciated.

The quickest and best option is a ROM emulator - I recommend the Artec
dongle, which was actually developed for a Geode platform:

http://www.coreboot.org/Artecgroup_programmable_LPC_dongle

Using a good ROM emulator results in a faster turn around cycle then JTAG,
and is more reliable too. 

Jordan

-- 
Jordan Crouse
Systems Software Development Engineer 
Advanced Micro Devices, Inc.





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