Hi Mike,
We are very seriously considering changing all our designs to use the new
ColdFire MCF5282, not because of any problems with the DSP56F807 chip, but
because there is no good development software available for it, only
CodeWarrior. Each new release of CodeWarrior seems to have a greater quantity
of bugs, and much more serious bugs, than the previous release. Sort of like
buying software from Microsoft. At least with the MCF5282, you have other
options. In all of our designs, the MCF5282 is a "drop-in" replacement
for the
DSP56F807, at almost exactly the same price, and with a huge memory size and
performance increase. We estimate that if the MCF5282 had been available 3
years ago, and we had chosen it for our new designs, all of our new products
would have been launched over 8 months ago. That translates into increased
revenues and reduced development costs totalling well into the six-figure
range.
I am also a big fan of Motorola's processors, and have been designing them
into
new products for over 26 years. I was one of the first people in Canada to
get
one of the MEK6800D2 kits in 1976 (I still have it, and its documentation, at
home). I have designed products using MC6802, MC68701, MC68302, and now
DSP56F807 chips as the CPU. It was only my long and very positive prior
experience with Motorola devices (analog as well as digital) that convinced
me
to spend huge amounts of extra time, for no additional pay, and which saved
Motorola's (and Metrowerks') bacon here at PMC (and apparently at
other
companies as well, due to my postings on the motoroladsp discussion group).
Yes, it is a small world! If you are ever in the Vancouver B.C. area, you
should drop in here to see our facility. I would be pleased to show you
around,
and maybe we could go to a local pub for lunch and a beer (or 2 or 3). :-)
Best Regards,
Art
-----Original Message-----
From: Mike Lindsey [mailto:]
Sent: Tuesday, December 03, 2002 5:37 PM
To: Art Johnson
Subject: RE: [motoroladsp] DSP56F807 and motor servo application
Art,
I appreciate your response to my post. I had not considered using
the fast interrupts for quadrature decoding.
After reading your post concerning the quality of the CodeWarrior
tools for the DSP56800, I am starting to have doubts about staying
with Motorola for my servo project. I have used Mot. processors
almost exclusively for 20+ years, however I am not impressed
with CodeWarrior for the 'HC908 family, and it sounds like
CodeWarrior for the DSP56800 is even worse. Apparently you
have developed a lot of code using the DSp56800 tools. Given the
chance to re-evaluate your processor selection would you still
choose the DSP56800?
I took a look at the PMC web site and realized I am working on a
project ( not the 4 axis servo ) to control a PMC pitch controller,
installed on a Washington
State Ferry. Small world!
Regards,
Mike Lindsey
> -----Original Message-----
> From: Art Johnson [mailto:]
> Sent: Tuesday, December 03, 2002 7:43 AM
> To: ;
> Subject: RE: [motoroladsp] DSP56F807 and motor servo application
> It should be relatively simple to create the two additional
> quadrature decoder channels in software. Each quadrature decoder
> channel would use two Timers in the same Quad Timer Module. To
> get the speed you need, you will have to use "Super Fast"
> interrupts, full details on how to do this is in my message "RE:
> [motoroladsp] Measuring PW using Quad Timer Captures" that I sent
> on Wednesday November 27, 2002, at 4:59am.
>
> If you also need to include the Index and Home signals, that is a
> bit more difficult, but still quite doable in my opinion. It
> becomes a bit trickier for Quad Timer C, because you don't have
> I/O pins for Timers C2 and C3, but two of the GPIO pins could be
> used for the Index and Home signals in this case.
>
> I hope this information is helpful to you, please let me know if
> you have any more questions.
>
> Regards,
>
> Art Johnson
> Senior Systems Analyst
> PMC Prime Mover Controls Inc.
> 3600 Gilmore Way
> Burnaby, B.C., Canada
> V5G 4R8
> Phone: 604 433-4644
> FAX: 604 433-5570
> Email:
> http://www.pmc-controls.com
>
> -----Original Message-----
> From: Mike Lindsey [mailto:]
> Sent: Monday, December 02, 2002 12:41 PM
> To:
> Subject: [motoroladsp] DSP56F807 and motor servo application
> I am considering the '56F807 for an application
> to control 4 DC motors, using a position PID control
> loop for each motor, with encoder feedback. I would
> need to two additional quadrature decode channels.
>
> I would appreciate any comments/suggestions with regards
> to the suitability of the '56F807 for this application.
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