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From: Stanley Starinski on 14 May 2010 18:52
Hi,

There's confusion between two newest Energy Meter's ref. designs:
MCP3909-1PH1 and MCP3909-PM1:
Energy Meter Reference Designs (boards/kits) info at MCP website is
conflicting - the relation between two kits is undefined and 70% of required
information for these two is hidden, which requires "detective" skills from
anyone pondering the selction of either board or both.

So, today I purchased "Microchip MCP3909RD-1PH1 SinglePhase EnergyMeter, $99
at Digikey. Not what I wanted (wanted MCP3909-PM1 instead), but was forced
to buy that + will buy second board (MCP3909-PM1) as soon as available.
Here's a problem (that makes deciding between 2 boards confusing). Two
things:

1) MCP3909RD-1PH1 product webpage was OK entire week while I studied it
(@MCP website), then suddenly MCP marked it as "temporarily unavailable";
and after checking its Application Software (runs on PC) + Firmware (runs on
MCU, so two downloads) I discovered they appear outdated (2007) yet Hardware
(demoboard itself) & Manual are fresh-new (Dec2009 to Feb2010); a possible
explanation is those wares were copied (adapted) from older three-phase
demoboard. OK, but Firmware looks suspicious also because #include statement
refers to a completely different MCU chip - 1825K20 which is present in
MCP3909-PM1 demoboard, but NOT in this MCP3909-1PH1 (this one is according
to all docs is using 18F85J90), also other strange things in Assembler code
are raising suspicion that wrong Firmware is posted at MCP site!?
But let's assume I am wrong and Firmware works fine. However it's
Assembler - C language version for this Demoboard would be better because
speed is NON-isse when processing single phase 50/60Hz AC current signal,
while C code makes it immensely easier to modify (or understand how it
works). Whose idea was it to still use Assembler in a new DEMOboard design
(year2010)? Looks like someone with "experience baggage" coming from the
early Assembler days. There're many cases where Assembler is a must - e.g.
DSP signal processing for RF signals, in thi scase it's counterproductive.
Also:
It uses Serial interface to PC, not USB (unless I am mistaken), so why
Serial in 2010? Yes Serial is easier and straighforward to work with MCU's,
versus USB stack; but really guys it's 2010 - now I have to stick an FTDI
chip (translator) so my boss wouldn't complain on Serial-to-USB dongle
hassle.

Now the docs:
There's one Microchip PDF doc dated by year2010 which lists MCP3909-1PH1,
another PDF also dated by year2010 only mentions MCP3909-PM1, and yet
another PDF mentions both - is Microchip going thru "problem fixing" or
"tentative decision" for these two boards? Note: all three PDF's are
entitled the same "Energy Metering Solutions from Microchip" or similar (I
maynot copied Title here exactly) -->their "Development tools" sections. If
you try to search MCP website for these 2 boards - you'll be surprised by
the lack of or conflicting info (I found some PDF's by doing a complicated &
long search instead of straightforward search for MCP3909-PM1 or -1PH1)

So in light of MCP website marking MCP3909-1PH1 today as "temporarily
Unavailable"- what's going on with it? It's pulled out of "MicrochipDirect",
but "Digikey" had 5 in stock so I bought one yesterday. Was it "pulled off
shelf" due to a discovered problem? If so how would I get updated if I
already bought current version today?

2) There's a related Ref.Design/DevBoard (kit) part# MCP3909RD-PM1 I am MORE
interested in it than in the one purchased today (MCP3909RD-1PH1), but
MCP3909-PM1 is still marked as "Coming Soon" May I ask this:

How long to wait until it's available for sale? Can I get SOMETHING for it
now, as I am 95% likely to buy it but eager to see some docs:
Schematics + SOURCE CODE are most important (but boardlayout/Gerbers not
expecting now, though would be appreciated). I have your MCP3909-1PH1, looks
related but not the same, what's the relation between two? I don't mind if
MCP3909-PM1 docs are still "in flux" and not finalized, just wanted to see
any docs + software for it.
Also I HOPE IT'S USING USB, NOT SERIAL PORT!!!

After a lengthy search, I was lucky to find only an Application Note AN1291
referring to this Dev.Board MCP3909-PM1 Again I say "lucky" as most people
would not spend that much searching for something that appears to be
missing. It's just a short Application Note, not a manual, no schematics
(!), no software (application and/or Firmware), nothing yet.

So to conclude I hope Microchip Engineer(s) can comment on what's going on
with these two Power/Energy Meter Reference Designs, why documentation &
Software is "fragmented" and confusing. I also hope for C-language software
& USB-to-serial solution for the one I already bought MCP3909-1PH1, and
schematics/software/docs for the one coming up: MCP3909-PM1.

======================================
UPDATE - 28Feb2010:
Here's a clarification which may introduce you to these two great
Reference Design Boards from Micrchip and the only way to locate their
webpages:

A) Some sources use slightly different part#'s for these two boards:
MCP3909RD-PM1 and MCP3909RD-1PH1 which is the same except with 'RD" added
(reference Design).

B) Best method of locating Microchip webpage srelated to it is by going to:
MCP Home --> Products-->DevelopmentTools-->Analog and Interface
Demo/EvaluationTools -->select icon for "MixedSignal/EnergyMeasurements"
If you try to search MCP website or even Google entire Web for these two
part#'s, not much comes up except a few useless PDF's, only one of which has
importance.
You have to instead go thru navigation I provided above.

I spoke with Microchip by phone and engineers are looking into this
mix-up/confused information and ordering problem, a Ticket was created.
These boards are great in Design time-reduction, yes it costs approx $200
total (so far $99+shipping, as second board is still not orderable) but
better than re-inventing something Microchip already did fine.
======================================


=========================
Stan Starinski
Phone (mobile): +1 (646) 416-2052
Web: www.Interengineers.org www.Nanoinfocenter.com Currently OFF for
maintenance

Consulting Engineer (EE+ME, ECAD+MCAD [3D/2D]), R&D + Prototype,
Embedded/Firmware ["C" or ASM for Microcontrollers], computers).


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