Forums

reset problem with 56807

Started by ljube20022000 November 22, 2002
My problem is that i can't reset the DSP after i download new code
via JTAG port. Essentially I need to turn the power off and on in
order for DSP to start executing the code. My reset signal stays low
for about 200ms and i think that should be more than enough to reset
DSP. Should i do something else after the code is loaded to DSP, is
there any portion of memory that needs to be flushed before it starts
executing? I would appreciate any information regarding this.



Well, this might seem a little obvious but are you clicking the run button? We have seen some strange instances where the DSP hangs after downloading to flash and the only way to run the code is by a hardware reset or cycling the power but once in a while we get reports that sometimes a push button reset does nothing to kick start the processor. We have not found a solution to this problem other than re-flashing the program, but I have noticed that logical errors in the code seem to amplify this problem. A not so trust worthy indication that you are headed for trouble is if your program is not jumping into main() after downloading. Sometimes the compiler just blows up and we end up having to stop the down loader in the middle of the process, reset the board or kill the power and flash again. Luckily this doesn't happen very often to warrant serious attention but the aforementioned fix seems to resolve the problem. Lastly, you might want to check that your power source is as clean as possible.
 
    Sorry this is not much help but I thought I would share this info just so you don't start ripping your hair out and go on a hunger strike.
 
P.S. Its not your fault, your not alone.
 
-miramont
-----Original Message-----
From: ljube20022000 [mailto:l...@hotmail.com]
Sent: Friday, November 22, 2002 11:48 AM
To: m...@yahoogroups.com
Subject: [motoroladsp] reset problem with 56807

My problem is that i can't reset the DSP after i download new code
via JTAG port. Essentially I need to turn the power off and on in
order for DSP to start executing the code.  My reset signal stays low
for about 200ms and i think that should be more than enough to reset
DSP.  Should i do something else after the code is loaded to DSP, is
there any portion of memory that needs to be flushed before it starts
executing?  I would appreciate any information regarding this.


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I think your problem is that JTAG/OnCE is still in
debug mode after the code is downloaded into flash.
You must reset DSP and its on-chip JTAG/OnCE at same
time. The solution can be found in Motorola FAQ
database. The following Q&A was copied from Motorola
web site. I strongly recommend everyone who uses
Motorola products to use this database.

http://e-www.motorola.com/cgi-bin/faq.cgi

Question:
The 56F80x/56F82x DSP on my production board sometimes
fails to boot properly on power-up when I'm not
debugging. What could be wrong?
Answer:
The problem stems from the TSRT\ pin of the JTAG port.
(On power-on the JTAG port comes up in an unknown and
unpredictable state.) When you are debugging TRST\ is
controlled by Codewarrior. When not debugging it
should be tied low. One way to ground it is via a zero
ohm resistor. (Just remove the resistor for debug.) Or
to save cost just ground TRST\ pin through a trace.
(Then just cut the trace for debugging, otherwise
leave it alone.) On Motorola EVMs just jumper pins 2
and 14 of the JTAG connector

Charlie W

--- ljube20022000 <> wrote:
> My problem is that i can't reset the DSP after i
> download new code
> via JTAG port. Essentially I need to turn the power
> off and on in
> order for DSP to start executing the code. My reset
> signal stays low
> for about 200ms and i think that should be more than
> enough to reset
> DSP. Should i do something else after the code is
> loaded to DSP, is
> there any portion of memory that needs to be flushed
> before it starts
> executing? I would appreciate any information
> regarding this. >


__________________________________________________



Thanks, that was a problem. TRST\ signal stayed high after
programming my board causing not complete reset of the DSP.

--- In motoroladsp@y..., Charlie W <charliewtx@y...> wrote:
> I think your problem is that JTAG/OnCE is still in
> debug mode after the code is downloaded into flash.
> You must reset DSP and its on-chip JTAG/OnCE at same
> time. The solution can be found in Motorola FAQ
> database. The following Q&A was copied from Motorola
> web site. I strongly recommend everyone who uses
> Motorola products to use this database.
>
> http://e-www.motorola.com/cgi-bin/faq.cgi
>
> Question:
> The 56F80x/56F82x DSP on my production board sometimes
> fails to boot properly on power-up when I'm not
> debugging. What could be wrong?
> Answer:
> The problem stems from the TSRT\ pin of the JTAG port.
> (On power-on the JTAG port comes up in an unknown and
> unpredictable state.) When you are debugging TRST\ is
> controlled by Codewarrior. When not debugging it
> should be tied low. One way to ground it is via a zero
> ohm resistor. (Just remove the resistor for debug.) Or
> to save cost just ground TRST\ pin through a trace.
> (Then just cut the trace for debugging, otherwise
> leave it alone.) On Motorola EVMs just jumper pins 2
> and 14 of the JTAG connector
>
> Charlie W
>
> --- ljube20022000 <ljube172@h...> wrote:
> > My problem is that i can't reset the DSP after i
> > download new code
> > via JTAG port. Essentially I need to turn the power
> > off and on in
> > order for DSP to start executing the code. My reset
> > signal stays low
> > for about 200ms and i think that should be more than
> > enough to reset
> > DSP. Should i do something else after the code is
> > loaded to DSP, is
> > there any portion of memory that needs to be flushed
> > before it starts
> > executing? I would appreciate any information
> > regarding this.
> >
> >
> > __________________________________________________
>