Lpc2000

----- Original Message ----- 

From: "martin de lange" <martin_de_lange@...>
To: <lpc2100@yahoogroups.com>
Sent: Tuesday, February 03, 2004 4:56 AM
Subject: [lpc2100] JTAG port


GlacierWhy does the uC have two JTAG ports ?

The JTAG ports are shared with I/Os; having two JTAG ports allows debugging
without interference with a required I/O function.

Leon

Do you mean that one would sometimes use the one JTAG port and at other
times use the other accoording to which I/O you wanted to use ?

I have also seen at times that users at times cannot get the second port to
work for debug and or flashing.

----- Original Message ----- 
From: "Leon Heller" <leon_heller@...>
To: <lpc2100@yahoogroups.com>
Sent: Tuesday, February 03, 2004 9:14 PM
Subject: Re: [lpc2100] JTAG port


>
> ----- Original Message ----- 
> From: "martin de lange" <martin_de_lange@...>
> To: <lpc2100@yahoogroups.com>
> Sent: Tuesday, February 03, 2004 4:56 AM
> Subject: [lpc2100] JTAG port
>
>
> GlacierWhy does the uC have two JTAG ports ?
>
> The JTAG ports are shared with I/Os; having two JTAG ports allows
debugging

> without interference with a required I/O function.
>
> Leon
>
>
>
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----- Original Message ----- 

From: "martin de lange" <martin_de_lange@...>
To: <lpc2100@yahoogroups.com>
Sent: Tuesday, February 03, 2004 8:23 AM
Subject: Re: [lpc2100] JTAG port


> Do you mean that one would sometimes use the one JTAG port and at other
> times use the other accoording to which I/O you wanted to use ?

Yes, it's mentioned in the data sheet.

>
> I have also seen at times that users at times cannot get the second port
to
> work for debug and or flashing.

I think that Philips has stated that the second JTAG port cannot be used for
programming, only debug.

Leon

Leon Heller wrote:

> ----- Original Message ----- 
> From: "martin de lange" <martin_de_lange@...>
> To: <lpc2100@yahoogroups.com>
> Sent: Tuesday, February 03, 2004 8:23 AM
> Subject: Re: [lpc2100] JTAG port
> 
> 
> 
>>Do you mean that one would sometimes use the one JTAG port and at other
>>times use the other accoording to which I/O you wanted to use ?
> 
> 
> Yes, it's mentioned in the data sheet.
> 
> 
>>I have also seen at times that users at times cannot get the second port
> 
> to
> 
>>work for debug and or flashing.
> 
> 
> I think that Philips has stated that the second JTAG port cannot be used for
> programming, only debug.
> 

Where? That's a pretty important piece of info. If that's the case then 
this part isn't as useful as it looks at first glance. If you need the 
primary JTAG for debug and programming then you lose those pins and the 
trace pins (from my understanding).

Sharing JTAG pins with I/O is an understandable practice from the 
manufacturer's standpoint, but from mine it makes designing things alot 
more difficult -- its pretty hard to assign any useful function to the 
pins that are used by the JTAG. You're almost better off programming it 
via the serial port and using 1-line diagnostics to debug like you have 
to do on the PIC <G>.

Brian


-- 
-----------------------------------------------------
Brian C. Lane (W7BCL)                      Programmer
www.shinemicro.com   RF, DSP & Microcontroller Design

--- In lpc2100@yahoogroups.com, "Brian C. Lane" <brian@s...> wrote:
> Leon Heller wrote:
> 
> > ----- Original Message ----- 
> > From: "martin de lange" <martin_de_lange@x...>
> > To: <lpc2100@yahoogroups.com>
> > Sent: Tuesday, February 03, 2004 8:23 AM
> > Subject: Re: [lpc2100] JTAG port
> > 
> > 
> > 
> >>Do you mean that one would sometimes use the one JTAG port and 
at other
> >>times use the other accoording to which I/O you wanted to use ?
> > 
> > 
> > Yes, it's mentioned in the data sheet.
> > 
> > 
> >>I have also seen at times that users at times cannot get the 
second port
> > 
> > to
> > 
> >>work for debug and or flashing.
> > 
> > 
> > I think that Philips has stated that the second JTAG port cannot 
be used for
> > programming, only debug.
> > 
> 
> Where? That's a pretty important piece of info. If that's the case 
then 
> this part isn't as useful as it looks at first glance. If you need 
the 
> primary JTAG for debug and programming then you lose those pins 
and the 
> trace pins (from my understanding).
> 
> Sharing JTAG pins with I/O is an understandable practice from the 
> manufacturer's standpoint, but from mine it makes designing things 
alot 
> more difficult -- its pretty hard to assign any useful function to 
the 
> pins that are used by the JTAG. You're almost better off 
programming it 
> via the serial port and using 1-line diagnostics to debug like you 
have 
> to do on the PIC <G>.
> 
> Brian
> 
> 

Hi Brian !

And how about programming it using the serial port and debugging 
with the secondary JTAG ? It is possible?

Juanjo

On Tue, Feb 03, 2004 at 09:01:12AM -0800, Brian C. Lane wrote:
> Leon Heller wrote:
> 
> > ----- Original Message ----- 
> > From: "martin de lange" <martin_de_lange@...>
> > To: <lpc2100@yahoogroups.com>
> > Sent: Tuesday, February 03, 2004 8:23 AM
> > Subject: Re: [lpc2100] JTAG port
> > 
> > 
> > 
> >>Do you mean that one would sometimes use the one JTAG port and at other
> >>times use the other accoording to which I/O you wanted to use ?
> > 
> > 
> > Yes, it's mentioned in the data sheet.
> > 
> > 
> >>I have also seen at times that users at times cannot get the second port
> > 
> > to
> > 
> >>work for debug and or flashing.
> > 
> > 
> > I think that Philips has stated that the second JTAG port cannot be used for
> > programming, only debug.
> > 
> 
> Where? That's a pretty important piece of info. If that's the case then 
> this part isn't as useful as it looks at first glance. If you need the 
> primary JTAG for debug and programming then you lose those pins and the 
> trace pins (from my understanding).
> 
> Sharing JTAG pins with I/O is an understandable practice from the 
> manufacturer's standpoint, but from mine it makes designing things alot 
> more difficult -- its pretty hard to assign any useful function to the 
> pins that are used by the JTAG. You're almost better off programming it 
> via the serial port and using 1-line diagnostics to debug like you have 
> to do on the PIC <G>.

one has to wonder in the days of high density packing why giving
4-5 pins a special function is so abhorent to these manufacturers.

-- 
Ben

Q:      What's a light-year?
A:      One-third less calories than a regular year.

----- Original Message ----- 

From: "Brian C. Lane" <brian@...>
To: <lpc2100@yahoogroups.com>
Sent: Tuesday, February 03, 2004 5:01 PM
Subject: Re: [lpc2100] JTAG port


> Leon Heller wrote:
>
> > ----- Original Message ----- 
> > From: "martin de lange" <martin_de_lange@...>
> > To: <lpc2100@yahoogroups.com>
> > Sent: Tuesday, February 03, 2004 8:23 AM
> > Subject: Re: [lpc2100] JTAG port
> >
> >
> >
> >>Do you mean that one would sometimes use the one JTAG port and at other
> >>times use the other accoording to which I/O you wanted to use ?
> >
> >
> > Yes, it's mentioned in the data sheet.
> >
> >
> >>I have also seen at times that users at times cannot get the second port
> >
> > to
> >
> >>work for debug and or flashing.
> >
> >
> > I think that Philips has stated that the second JTAG port cannot be used
for
> > programming, only debug.
> >
>
> Where? That's a pretty important piece of info. If that's the case then
> this part isn't as useful as it looks at first glance. If you need the
> primary JTAG for debug and programming then you lose those pins and the
> trace pins (from my understanding).

I think it's in the User Manual.

Leon

--- In lpc2100@yahoogroups.com, Ben Dooks <ben@f...> wrote:

> one has to wonder in the days of high density packing why giving
> 4-5 pins a special function is so abhorent to these manufacturers.
> 
> -- 
> Ben
> 
> Q:      What's a light-year?
> A:      One-third less calories than a regular year.

Hi Ben,

what about looking at it like this. JTAG pins are dedicated pins, no
secondary function. You need more than the available I/O pins? Well
that's probably exactly what other customers told Philips as well. Now
assuming the same number of I/O pins but 5 dedicated JTAG pins leaves
us with a 53-pin package;-)
Seriously, every pins is money and increases the size of the package.
I consider the dual functionality a compromise for those of us who
actually need the small package, more I/O AND JTAG. You or anybody
else should feel free to use (probably the secondary) JTAG as
dedicated pins.
Btw. the 64-pin device LPC2114... has more I/O pins and you can use
the JTAG pins dedicated.

Cheers, Bob

Ben Dooks wrote:

> 
> one has to wonder in the days of high density packing why giving
> 4-5 pins a special function is so abhorent to these manufacturers.
> 

What would ROCK is a JTAG connector mounted on the top of the chip...

ABS