PMB-648 GPS Part# 28500 - Wrong Datasheet?

Jorge P · 2010-01-20 05:52

I just purchased the PMB-648 GPS unit, I checked the wiring diagram that is listed on the product page and I noticed it has a different pin/wiring, its for the PMB-248...

I can't find the documentation on the PMB-648, it just takes me to the PMB-248 page...

Anyways, here is the pinout of the PMB-648

White wire - GND
Green wire - RX
Black wire ·- TX
Red wire··· - VIn
Blue wire···- RXD
Yellow wire - TXD

that is how it is listed on the GPS·board.

I am trying to connect this to the Propeller too, I am new to both GPS and the Propeller so any help would be much appreciated.

Thanks

Jorge

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Post Edited (Jorge P) : 1/20/2010 6:55:07 AM GMT

Ken Gracey · 2010-01-20 09:39

Jorge P - just a quick note - I've asked Chris to take a look at this post and fix the documentation.

I had this GPS module working on my desk last week with parts from OBEX. Chris will provide some pointers for you.

How did you buy this GPS? It's not on our web site yet but we have 500 units in stock.

Ken Gracey

Jorge P · 2010-01-20 18:37

Ken Gracey (Parallax) said...
Jorge P - just a quick note - I've asked Chris to take a look at this post and fix the documentation.

I had this GPS module working on my desk last week with parts from OBEX. Chris will provide some pointers for you.

How did you buy this GPS? It's not on our web site yet but we have 500 units in stock.

Ken Gracey

I actualy purchased the PMB-248 and this was sent, I assumed that the order processing dept at parallax either made a mistake, or that they were temporarily out of stock with the PMB-248.· As for you having 500 in stock, you might want to lower that to 499,

...

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Post Edited (Jorge P) : 1/20/2010 7:12:32 PM GMT

Chris Savage · 2010-01-20 19:57

Jorge P,

I just checked the PMB-248 and your pin assignments are incorrect. Conecting them that way will damage the module. If you look closer you will see that those pads on the top of the PCB do not connect directly the wires in the same order below them. This is a multi-layer PCB and for whatever reason they are placed in that order on top of the PCB and it varies from the wiring of the connector. You can verify this by connecting a continuity checker to each pad and the other side to the corresponding wire to match them up. But the wiring diagram is correct.

Best Regards,

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Chris Savage

Parallax Engineering
Check out the new Savage Circuits TV!
·

Jorge P · 2010-01-20 21:21

Chris Savage (Parallax) said...
You can verify this by connecting a continuity checker to each pad and the other side to the corresponding wire to match them up. But the wiring diagram is correct.

Best Regards,

·I should have done that, Thanks for the reminder.... I actualy had two DMM's·right next to me as I was looking at that.

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Ken Gracey · 2010-01-20 22:08

@Jorge P,

Consider yourself fortunate - you got the latest and highest performance GPS from Parallax. I'm attaching some specs on the PMB-648 for you since the product is not for sale on-line yet. It's a SiRFStarIII chipset with tracking of 20 satellites and quick signal lock-on. We have two versions of it, too, with and without antenna. The one you have includes internal antenna with no connection for external.

The retail price will be $30-40. I've already provided everything to WebDev to put the two new GPS products (and a nice comparison table) on our web site. Just waiting for them to finish now.

Enjoy the PMB-648!

Sincerely,

Ken Gracey

kf4ixm · 2010-01-20 22:28

@ Ken Gracey
Will the PMB-648 support "smart mode" as well as "raw mode" like the #28146?

Jorge P · 2010-01-20 22:35

Ken Gracey (Parallax) said...
@Jorge P,

Consider yourself fortunate - you got the latest and highest performance GPS from Parallax. I'm attaching some specs on the PMB-648 for you since the product is not for sale on-line yet. It's a SiRFStarIII chipset with tracking of 20 satellites and quick signal lock-on. We have two versions of it, too, with and without antenna. The one you have includes internal antenna with no connection for external.

The retail price will be $30-40. I've already provided everything to WebDev to put the two new GPS products (and a nice comparison table) on our web site. Just waiting for them to finish now.

Enjoy the PMB-648!

Sincerely,

Ken Gracey

Since I dont want anyone to fry their PMB-648 by connecting it according to the pinout I displayed in the first post, I think I should note that my first post, I·was inacurate with the wiring, and it is in-fact the same pinout/wiring colors as the PMB-246.

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Ken Gracey · 2010-01-20 22:41

@kf4ixm, raw mode. There are actually two new models PMB-648 and PMB-688.

The current 28146 product is being upgraded to use the PMB-648, however, so it will support the Smart Mode in future production runs.

Are you using a BASIC Stamp?

Ken Gracey

kf4ixm · 2010-01-20 22:53

@ Ken
Yes i am, i have the bs2 and the 28146 right now. i like the smart mode function just for it's simplicity in coding. when the upgraded 28146 comes out, will it have the option with/without antenna?

Ken Gracey · 2010-01-20 23:49

We'll use the model without external antenna connection (will use internal antenna).

I see why you want Smart Mode - much easier with the BS2.

Ken

Jorge P · 2010-01-27 00:02

I finaly got around to hooking this up and testing it.
It was extremely accurate, putting the cordinates into google maps, it put an arrow right on my car.

Rec.:852 Ver.:852 Fail:0 (Decoded RMC:236 GGA:237 GLL:0 GSV:141 GSA:237)
  Last decoded NMEA sentence : RMC
             GPS Data Status : Valid
         GPS Navigation Mode : Differential GPS
        Position Fix Quality : DGPS SPS, Fix Valid
  Positioning Mode Selection : Automatic 2D/3D
     Actual Positioning mode : 3D
    ID of Satellites in View :   14  22  26  19  18  11   9  31  27  32   3   6
                   Elevation :   88  61  59  25  25  17  17  13  12  11   9   9
                     Azimuth :  216  82  52 255  94 312  39 175  35 282 230 221
             Signal Strength :   26  39  39  30  32  20  31  23  25  16  27  --
ID of Satellites Used in Fix :   19   9  31   3  18  14  26  22  27  11
            PDOP, HDOP, VDOP :   1.4  0.8  1.1
 
 Day Month Year(AD) as LONGs : 26  1  2010
 UTC Hour Min. Sec. as LONGs : 23  53  11
 Latitude in degres as FLOAT : 45.78087
Longitude in degres as FLOAT : -111.1853
Speed Over Gnd [noparse][[/noparse]knots] FLOAT : 0
Course Over Gnd [noparse][[/noparse]degs] FLOAT : 257.09
Magn. Variation [noparse][[/noparse]degs] FLOAT : --.-
Alt. at Mean Sea Lev.  FLOAT : 1367.9 M
 MSL relative to WGS84 FLOAT : -17.3 M
 
  Actual NMEA Data in Buffer :
GPRMC,235311.000,A,4546.8518,N,11111.1164,W,0.00,257.09,260110,,,D

I think it shows 12 satalites but 10 got a fix if I am reading it right.· Now everyone can add me to their maps [noparse]:)[/noparse]

I had some problems with the PC not seeing my propeller, I noticed the lights/leds were dim so I replaced my power supply and loaded the GPS_Float_Demo.· Yellow wire to pin 7(as per demo), Blue wire to pin 8(as per demo), black to ground, and red to +3.3V.

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hover1 · 2010-01-27 14:56

Thanks for the update. That's very good news! How accurate is the reported Altitude?
Jim

Jorge P said...
I finaly got around to hooking this up and testing it.
It was extremely accurate, putting the cordinates into google maps, it put an arrow right on my car.

Jorge P · 2010-01-28 03:24

I am not sure how high above sea level I am, but this location is in the rocky mountains. I am sure you can find out using a topigraphical map of the GPS location just to be sure. I think it is roughly 5,000 ft, using google to convert meters to feet I get 1,367.9 meters = 4,487.86089 feet. Which is fairly accurate. My town is Belgrade Mt.! Bozeman Mt. (the next town over) is 4,795 feet above sea level, Belgrade is lower in the vally so the sea level reading seems pretty accurate, but it is roughly a 300 foot differance.

Pluss my readings were done from indoors, I am sure an outside reading would be more accurate. Next monday/tuesday I will try to connect this to my laptop and get a reading from outside.

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hover1 · 2010-01-28 21:13

Ken,

Will the new model with Smart Mode still be based on the SX or will it be upgraded to the Propeller? Propeller seems like the natural progression like the Servo Controller. Although a few pins wasted on the processor, you could put a serial and parallel LCD output on the GPS board.

Best,

Jim

Ken Gracey (Parallax) said...
@kf4ixm, raw mode. There are actually two new models PMB-648 and PMB-688.

The current 28146 product is being upgraded to use the PMB-648, however, so it will support the Smart Mode in future production runs.

Are you using a BASIC Stamp?

Ken Gracey

kf4ixm · 2010-01-28 21:16

hover1 said...

..., you could put a serial and parallel LCD output on the GPS board.

Best,

Jim

·

Now i like that idea, serial out to a 4x20 for lat, long, sats and elevation!!!!

Duffer · 2010-01-28 22:18

From the current "Front Page" ad at Parallax: "Up to 20 satellites for under $40 each". That seems a bit pricey,eh? 20 x $40 = $800! That's an expensive GPS!

I don't think I could afford even the 12 channel model at that price.

Duffer

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PMB-648 GPS Part# 28500 - Wrong Datasheet?

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