[U-Boot-Users] BDI2000 with pxa255

Paugam Luc luc.paugam at thomson.net
Wed Jan 26 10:49:31 CET 2005

The BDI2000 systematically try to reset the CPU if the JTAG's Bypass check fails. So, there is no issue with the reset line even if it is asserted by the BDI2000.

Many think can introduce issues with your JTAG:
	- If you have several chips in your chain, the chain is broken somewhere.
	- If you have several chips in your chain, the POST or PRE "scan access" to your CPU are wrongs.
	- Your CPU has not properly selected its JTAG port (e.g. there is an errata on the AT91RM9200).
	- Wrong firmware inside the BDI2000.
	- Wrong wiring of the JTAG connector
	- ...etc

Hope that helps.
Regards - Luc

-----Original Message-----
From: Hinko Kocevar [mailto:hinko at iskramedical.si] 
Sent: lundi 24 janvier 2005 16:49
To: Paugam Luc
Cc: u-boot-users at lists.sourceforge.net
Subject: Re: [U-Boot-Users] BDI2000 with pxa255

Paugam Luc wrote:
> Hi,
> There is a problem with your JTAG link or chain.
> The important line is: 
> 	- TARGET: Bypass check: 0x000000001 => 0x00000000
> It says roughly: (as you know, a JTAG chain is let say "a serial link looped") After setting all JTAG controllers into the JTAG chain to bypass mode, I sent a 1 (only 1 bit) and tried to get back this bit ... but in your case without success!

So, this could mean that other (TDI,TDO) JTAG lines do not operate 
properly - or is this consequently because target was not reseted properly?


hinko <dot> kocevar <at> iskramedical <dot> si
Hinko Kocevar, embedded systems developer
Iskra Medical d.o.o., Stegne 23, 1k LJ, SLO-EU

	"Aì rén"	|	[Analects XII:22]

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