Forums

Re: [c55x] CC and JTAG with other devices in the scan chain

Started by Jeff Brower June 3, 2003
Gagan-

> I guess better put the TI device as first
> CPU in the boundary scan chain. This might help. I
> only run homogenous mix of 8 TI DSPs in single chain.
> But havn't try on the hetrogenous mix of other CPUs
> Other thing is to slow the JTAG clock from 10.xx to
> 2.xx

Do you know how to slow the JTAG clock with Spectrum Digital XDS510PP emulator?
There have been a few times before we wanted to slow the clock for board debug
purposes. There is a "Speed" control in the SDConfig setup, but I think that is
a
host software transfer rate setting.

Jeff Brower
system engineer
Signalogic

> --- Arius - Rick Collins <> wrote:
> > The JTAG port is used both for debugging software in
> > development and for
> > boundary scan hardware test in production. Most of
> > the PLD vendors provide
> > support in their programming software for other
> > devices in the scan
> > chain. But I have received mixed advice on putting
> > TI DSPs in a scan chain
> > with other devices. TI has lots of literature
> > saying you can do this and
> > Code Composer seems to offer support for this. But
> > when I asked TI support
> > about it, they said they don't advise you to try it,
> > but to put the DSP on
> > its own JTAG port with no other devices.
> >
> > Seems TI can't make up its mind about whether or not
> > they wish to support
> > JTAG for boundary scan. Anyone have any experience
> > with this? Have you
> > used TI DSPs in a scan chain with other devices such
> > as FPGAs and MCUs?
> >
> >
> > Rick Collins
> >
> >
> >
> > Arius - A Signal Processing Solutions Company
> > Specializing in DSP and FPGA design
> > http://www.arius.com
> > 4 King Ave
> > 301-682-7772 Voice
> > Frederick, MD 21701-3110
> > 301-682-7666 FAX




David-

> I think you are correct about the speed issue. I think I've read that it's
> actually a delay parameter on the EPP/ECP interface between host PC
> the emulator box.
> I haven't checked it yet, but isn't there a jumper on the DSK board
> configuring the JTAG speed? I'll check as soon as I'm available for that
> and get an answer.

Thanks. I am hoping to hear that someone knows a way to do this inside the
Spectrum
Digital XDS510PP emulator, maybe deadbug a part or 2 and add some jumpers to
control
the clock rate, or similar. The issue for us is we're always bringing up new
C5xxx
and C6xxx hardware, and JTAG is sometimes a problem, especially TCK signal. For
example, we can't always put the JTAG header as close to the DSP chain as we
want, we
have a lot of high speed noise sources, etc.

Jeff Brower
system engineer
Signalogic

> -----Original Message-----
> From: Jeff Brower [mailto:]
> Sent: Tuesday, June 03, 2003 3:18 PM
> To: Gagan Singh
> Cc: ; ;
> Subject: Re: [c55x] CC and JTAG with other devices in the scan chain
>
> Gagan-
>
> > I guess better put the TI device as first
> > CPU in the boundary scan chain. This might help. I
> > only run homogenous mix of 8 TI DSPs in single chain.
> > But havn't try on the hetrogenous mix of other CPUs
> > Other thing is to slow the JTAG clock from 10.xx to
> > 2.xx
>
> Do you know how to slow the JTAG clock with Spectrum Digital XDS510PP
> emulator?
> There have been a few times before we wanted to slow the clock for board
> debug
> purposes. There is a "Speed" control in the SDConfig setup, but I think
> that is a
> host software transfer rate setting.
>
> Jeff Brower
> system engineer
> Signalogic
>
> > --- Arius - Rick Collins <> wrote:
> > > The JTAG port is used both for debugging software in
> > > development and for
> > > boundary scan hardware test in production. Most of
> > > the PLD vendors provide
> > > support in their programming software for other
> > > devices in the scan
> > > chain. But I have received mixed advice on putting
> > > TI DSPs in a scan chain
> > > with other devices. TI has lots of literature
> > > saying you can do this and
> > > Code Composer seems to offer support for this. But
> > > when I asked TI support
> > > about it, they said they don't advise you to try it,
> > > but to put the DSP on
> > > its own JTAG port with no other devices.
> > >
> > > Seems TI can't make up its mind about whether or not
> > > they wish to support
> > > JTAG for boundary scan. Anyone have any experience
> > > with this? Have you
> > > used TI DSPs in a scan chain with other devices such
> > > as FPGAs and MCUs?
> > >
> > >
> > > Rick Collins
> > >
> > >
> > >
> > > Arius - A Signal Processing Solutions Company
> > > Specializing in DSP and FPGA design
> > > http://www.arius.com
> > > 4 King Ave
> > > 301-682-7772 Voice
> > > Frederick, MD 21701-3110
> > > 301-682-7666 FAX



Gagan-

> The JTAG clock freq control is provided
> in the POD only. It is for the manufacure to give
> some kind of interface to do so. In my case we did
> use flexds emulators. They did provided control to
> change JTAG clock by jumper settings in the POD
> itself.

Ok, score one for Flexds emulators, that is an excellent feature. I think I
will
e-mail the Mike and Danny at Spectrum Digital and see what is their suggestion
on how
to do it with their units.

Jeff Brower
system engineer
Signalogic > Plus u have to specify the same in ur config file
> placed mostly in ..\ti\cc\bin
>
> Regards
> Gagan
>
> --- Jeff Brower <> wrote:
> > Gagan-
> >
> > > I guess better put the TI device as
> > first
> > > CPU in the boundary scan chain. This might help. I
> > > only run homogenous mix of 8 TI DSPs in single
> > chain.
> > > But havn't try on the hetrogenous mix of other
> > CPUs
> > > Other thing is to slow the JTAG clock from 10.xx
> > to
> > > 2.xx
> >
> > Do you know how to slow the JTAG clock with Spectrum
> > Digital XDS510PP emulator?
> > There have been a few times before we wanted to slow
> > the clock for board debug
> > purposes. There is a "Speed" control in the
> > SDConfig setup, but I think that is a
> > host software transfer rate setting.
> >
> > Jeff Brower
> > system engineer
> > Signalogic
> >
> > > --- Arius - Rick Collins <>
> > wrote:
> > > > The JTAG port is used both for debugging
> > software in
> > > > development and for
> > > > boundary scan hardware test in production. Most
> > of
> > > > the PLD vendors provide
> > > > support in their programming software for other
> > > > devices in the scan
> > > > chain. But I have received mixed advice on
> > putting
> > > > TI DSPs in a scan chain
> > > > with other devices. TI has lots of literature
> > > > saying you can do this and
> > > > Code Composer seems to offer support for this.
> > But
> > > > when I asked TI support
> > > > about it, they said they don't advise you to try
> > it,
> > > > but to put the DSP on
> > > > its own JTAG port with no other devices.
> > > >
> > > > Seems TI can't make up its mind about whether or
> > not
> > > > they wish to support
> > > > JTAG for boundary scan. Anyone have any
> > experience
> > > > with this? Have you
> > > > used TI DSPs in a scan chain with other devices
> > such
> > > > as FPGAs and MCUs?
> > > >
> > > >
> > > > Rick Collins
> > > >
> > > >
> > > >
> > > > Arius - A Signal Processing Solutions Company
> > > > Specializing in DSP and FPGA design
> > > > http://www.arius.com
> > > > 4 King Ave
> > > > 301-682-7772 Voice
> > > > Frederick, MD 21701-3110
> > > > 301-682-7666 FAX



Jeff,

If you are having problems with noise on long JTAG chains,
try to buffer the JTAG lines. I have seen boards with 16 C6000
DSPs on a single chain that worked just fine.
I guess the trick may be in keeping the JTAG lines well laid out on the PCB.

If it is too late for adding buffers, you can use an emulator that buffers the
JTAG signals right at the JTAG target header, before they go into
the several inches of the emulator cable.
I believe Signum is the only company that does it -see
www.signum.com/jtagjet.htm
It also lets you change the JTAG clock in steps from 1 kHz to 30 MHz
with software.
You can send us your board and we will test it at the desired JTAG clock
at no charge.

Jerry Lewandowski
Signum Systems Corp.
www.signum.com ----- Original Message -----
From: "Jeff Brower" <>
To: "Gagan Singh" <>
Cc: <>; <>; <>
Sent: Wednesday, June 04, 2003 8:36 AM
Subject: [c6x] Re: [c55x] CC and JTAG with other devices in the scan chain > Gagan-
>
> > The JTAG clock freq control is provided
> > in the POD only. It is for the manufacure to give
> > some kind of interface to do so. In my case we did
> > use flexds emulators. They did provided control to
> > change JTAG clock by jumper settings in the POD
> > itself.
>
> Ok, score one for Flexds emulators, that is an excellent feature. I think I
will
> e-mail the Mike and Danny at Spectrum Digital and see what is their suggestion
on how
> to do it with their units.
>
> Jeff Brower
> system engineer
> Signalogic > > Plus u have to specify the same in ur config file
> > placed mostly in ..\ti\cc\bin
> >
> > Regards
> > Gagan


Jerry-

> If you are having problems with noise on long JTAG chains,
> try to buffer the JTAG lines. I have seen boards with 16 C6000
> DSPs on a single chain that worked just fine.

We do that as much as possible, but in many cases we don't have room for
buffers, or
at least more than one set. The boards are typically small and dense, 10 layer
to
16-layer, two examples are shown at:

http://www.signalogic.com/sigc67xx_sodimm.htm

http://www.signalogic.com/sigc5441_sar_ptmc.htm

The first one gave us a lot of JTAG trouble because we needed a bus switch to
select
between CPLD JTAG and DSP JTAG chain, so we sacrificed the buffer, relying on
the
buffer on the base board. Bad move. The buffer is back on now, wedged in there
somehow.

> I guess the trick may be in keeping the JTAG lines well laid out on the PCB.

Yep we always pay very careful attention to that. We also leave zero-ohm Rs to
allow
the chain to be shortened at several points. But even an inch or so on a
gnd-protected clock trace layer can still be enough to cause problems with TCK,
it's
just very sensitive to any acquired noise. I would say this signal is not a
favorite
of our engineers.

> If it is too late for adding buffers, you can use an emulator that buffers the
> JTAG signals right at the JTAG target header, before they go into
> the several inches of the emulator cable.
> I believe Signum is the only company that does it -see
www.signum.com/jtagjet.htm
> It also lets you change the JTAG clock in steps from 1 kHz to 30 MHz
> with software.

With software? Those are very good features.

> You can send us your board and we will test it at the desired JTAG clock
> at no charge.

Yes I will keep this in mind! Thanks Jerry.

Jeff Brower
system engineer
Signalogic

> ----- Original Message -----
> From: "Jeff Brower" <>
> To: "Gagan Singh" <>
> Cc: <>; <>; <>
> Sent: Wednesday, June 04, 2003 8:36 AM
> Subject: [c6x] Re: [c55x] CC and JTAG with other devices in the scan chain
>
> > Gagan-
> >
> > > The JTAG clock freq control is provided
> > > in the POD only. It is for the manufacure to give
> > > some kind of interface to do so. In my case we did
> > > use flexds emulators. They did provided control to
> > > change JTAG clock by jumper settings in the POD
> > > itself.
> >
> > Ok, score one for Flexds emulators, that is an excellent feature. I think I
will
> > e-mail the Mike and Danny at Spectrum Digital and see what is their
suggestion on how
> > to do it with their units.
> >
> > Jeff Brower
> > system engineer
> > Signalogic
> >
> >
> > > Plus u have to specify the same in ur config file
> > > placed mostly in ..\ti\cc\bin
> > >
> > > Regards
> > > Gagan