Forums

[Fwd: Re: can't connect to target after flashburn]

Started by Jeff Brower March 4, 2004
Mike-

What can programming Flash do to hold up JTAG on the DSK board? It must be DSK
board
specific, because normally -- as long as C67xx reset is not held and JTAG
signals are
still connected and healthy - JTAG should be enabled. I suppose the CCS driver
is
doing something else it needs to initialize, not just JTAG, and the program
running
from Flash has somehow got in the way.

-Jeff

-------- Original Message --------
Subject: Re: [c6x] can't connect to target after flashburn
Date: Wed, 3 Mar 2004 21:34:50 -0800 (PST)
From: Mike Dunn <>
To: stino_rides <>,

Hello Stijn, It is possible for the programmation of the FLASH to prevent the
emulator from taking control. One way to get around the problem is to bring up
the
board in HPI boot mode. After reset the DSP will "hang", until the emulator
comes
up. The only trick is to "get there"... Since I do not know your capabilities
or
situation, I will provide a couple of suggestions. [Refer to the DSK schematics,
page
5, to see what is going on] IF YOU DO NOT UNDERSTAND ANY OF THE FOLLOWING,
IGNORE IT
OR GET HELP! 1. Use a fine "clip lead" to connect U20 pin 5 [a convenient, and
marked, corner pin] to ground [the JTAG connector pin 4 is easy]. you can leave
this
connected as long as you need it. 2. solder a very short piece of wire in the
R82
position - this will cause HPI boot to be permanent. 3. [my favorite] Run a
piece of
small gauge wire from "the R82 pad that connects to R83" to "the switched pin of
unused switch #4" [I think that it is the one near the board edge]. Use sw 4 to
enable/disable HPI boot mode.Happy "booting",mikedunn
stino_rides <> wrote:

Hi
I encountered a pretty severe problem today: i wanted to test the
flashburn program, I did this by burning the supplied FlashBlink
example,
The burned program does start without any problems, but now I cannot
connect to the c6711dsk anymore. ('Can't initialize target cpu etc.).
I tried everything (reset, power on/off) but it does not work..
I did not find any jumpers or so to disable booting from flash,
anyone knows what I can do?
Thanks,
Stijn



Hello Jeff,
 
I agree with you - if all is well.
 
it is true, JTAG is enabled - but it is a long journey for the JTAG signals to traverse from the JTAG clock domain to and from the CPU.  There are certain synchronizations and timing windows that must occur for emulation transactions to succeed [like halting the DSP for one].
 
I do not know for sure the exact cause and I have only known this situation to occur when the DSP was executing something other than legal code.  I speculate that one possible cause is a memory cycle starts but never ends - this would lock out emulation control until the cycle completes.
 
My most recent empirical evidence comes from the 6711 DSK.  I jumpered it to change the endianness and I could not get emulation control 90% percent of the time [since BE mode was 'booting' from the high byte of the data bus the DSP was eating garbage...].  I have also had similar experiences with "trashed flash".  I think the root of the problem has to do with "executing garbage" and an instruction set that is not fully decoded.
regards,
mikedunn
Jeff Brower <j...@signalogic.com> wrote:
Mike-

What can programming Flash do to hold up JTAG on the DSK board? It must be DSK board
specific, because normally -- as long as C67xx reset is not held and JTAG signals are
still connected and healthy - JTAG should be enabled. I suppose the CCS driver is
doing something else it needs to initialize, not just JTAG, and the program running
from Flash has somehow got in the way.

-Jeff

-------- Original Message --------
Subject: Re: [c6x] can't connect to target after flashburn
Date: Wed, 3 Mar 2004 21:34:50 -0800 (PST)
From: Mike Dunn
To: stino_rides , c...@yahoogroups.com

Hello Stijn, It is possible for the programmation of the FLASH to prevent the
emulator from taking control. One way to get around the problem is to bring up the
board in HPI boot mode. After reset the DSP will "hang", until the emulator comes
up. The only trick is to "get there"... Since I do not know your capabilities or
situation, I will provide a couple of suggestions. [Refer to the DSK schematics, page
5, to see what is going on] IF YOU DO NOT UNDERSTAND ANY OF THE FOLLOWING, IGNORE IT
OR GET HELP! 1. Use a fine "clip lead" to connect U20 pin 5 [a convenient, and
marked, corner pin] to ground [the JTAG connector pin 4 is easy]. you can leave this
connected as long as you need it. 2. solder a very short piece of wire in the R82
position - this will cause HPI boot to be permanent. 3. [my favorite] Run a piece of
small gauge wire from "the R82 pad that connects to R83" to "the switched pin of
unused switch #4" [I think that it is the one near the board edge]. Use sw 4 to
enable/disable HPI boot mode.Happy "booting",mikedunn
stino_rides wrote:

Hi
I encountered a pretty severe problem today: i wanted to test the
flashburn program, I did this by burning the supplied FlashBlink
example,
The burned program does start without any problems, but now I cannot
connect to the c6711dsk anymore. ('Can't initialize target cpu etc.).
I tried everything (reset, power on/off) but it does not work..
I did not find any jumpers or so to disable booting from flash,
anyone knows what I can do?
Thanks,
Stijn

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