Lpc2000

Marcus:

Comments next to your questions.

Regards,

Ian

--- In lpc2000@yahoogroups.com, Markus Meng <meng.engineering@b...> 
wrote:
> Hi Richard,
> 
> 
> 
> - concerning 2nd JTAG I wonder if I can use the very same
> JTAG ARM Adapter 2x10 Pin to connect to the 2ndary JTAG?
Ian > Yes, exactly the same.

> 
> - If so, I can make a board without the primary JTAG and
> it is still possible to debug code? Is this correct.
Ian > Yes, with the caveat to question three.

> 
> - I do not understand the disadvantages, if I make use of
> the 2nd JTAG only. It uses less pins than the primary, and
> I always need SW to enable it. Is this correct?
Ian > The secondary JTAG is enabled by software so you cannot get 
there unless you have the part FLASHed with the right code.  You 
cannot load a RAM based example unless the JTAG is enabled first 
which means the right part of code MUST be in FLASH first.  You can 
of course load a small application to enable the secondary JTAG via 
the serial port.

> 
> Best Regards
> Markus Meng
> 
> Richard schrieb:
> 
> >I am planning to use the secondary JTAG (LPC2104) in a design.  I 
> >have already been debugging (from flash) using the second JTAG by 
> >placing a firmware in flash to enable the second JTAG pins and 
then 
> >starting the debugger.
> >So, in the actual application, I will have to load the JTAG enable 
> >firmware everytime(via ISP)I want to debug or program via the 2nd 
> >JTAG port, correct?
> >I have dip switches in the design, could I use one of these to 
> >trigger software to write to PINSEL1 and enable the 2nd JTAG?
> >
> >Thanks
> >
> >Rich
> >
> >
> >
> >
> >
> >
> >
> >
> > 
> >Yahoo! Groups Links
> >
> >
> >
> > 
> >
> >
> >
> >
> >  
> >
> 
> -- 
> Mit freundlichen Grüssen
> Markus Meng
> 
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