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369 Views 1 Replies Last post: Nov 20, 2009 11:17 AM by kevinpking RSS
Tom Kooistra Newbie
Tom Kooistra
1 posts since
Nov 15, 2009
Currently Being Moderated

Nov 16, 2009 10:45 AM

H-UDI / JTAG

I am trying to create a boundary scan test for a SH series chip via jtag.  My interface seems to be functioning properly hardware wise and I can read out the idcode without an issue, but I am unable to do much more than that.

 

I get the impression from the datasheet that the chip / TAP controller / IR does not accept standard jtag commands while in standby, or I'm not dealing with the TRST properly on boot up.

 

Is it imparative to maintain TRST low during startup?  To initiate the Interrupt servicing?

 

It appears that the Instruction register always contains 1 for all 8 bits which would seem to indicate bypass mode all the time, though I believe its suppose to default to idcode?

 

Is it possible my IC is sitting in Hardware or Software Standby mode?

 

Any ideas?

kevinpking Newbie
kevinpking
70 posts since
Mar 4, 2009
Currently Being Moderated
Nov 20, 2009 11:17 AM in response to: Tom Kooistra
Re: H-UDI / JTAG

Hi Tom,

 

For this kind of question, you should really put the SH part number in the query.  Not all SH devices support boundary scan and may in fact look like BYPASS mode all the time.

 

Go to this website. http://resource.renesas.com/lib/jpn/superh/ibis_bsdl/en/sh12_download.html You will need MyRenesas Login (free) as these are covered by "click through" agreement.

 

If there is NO BSDL for the chip in question, it probably does not support boundary scan (and the JTAG is used for debug only).

Note there is a tab for SH1/SH2, SH3 and SH4.  Most of the SH3 and SH4 device have boundary scan, some SH1/SH2 devices have boundary scan.

 

If you have the BSDL, ignore most of this, but it still might help to have part number.

 

Hope this helps.


Regards,

Kevin

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