PG31 GPS USB Dev Board

From OpenCircuits
(Difference between revisions)
Jump to: navigation, search
(cleaned off vandelism)
Line 1: Line 1:
[ afl screensavers] [ macintosh support] [ japanese model] [ young  girls] [ property law spain] [ arican american inventors] [ take it down from the mast irish traitors] [ online encyclopedia] [ tree frogs] [ drop your pants bend over] [ country maps] [ share capital increase] [ leiter lites track lighting] [ act sister soundtrack] [ rewiring chandelier] [ ball licking] [ advisor financial independent uk] [ librarian jobs new york] [ 2 cloud dark guide weapon] [ suberbowl odds] [ ceiling fan direction winter] [ bird hunting] [ principal] [ us mexico border counties coalition] [ marie tira] [ 101 clubbing technique] [ american airline flight schedule] [ ix netcom com] [ used laptop computers] [ california southern university] [ watervliet high school] [ new movie rental release] [ lg lcd tv 42] [ wyoming valley health care systems] [ playboy bunny msn display picture] [ yama studio] [ girl pakistan] [ portland sea dogs] [ airwaves angel cd date release] [ airplane direction make paper] [ a genuine college degree] [ phonics videos] [ microtech automatic knife] [ this operation requires the] [ aaron] [ inspection pipeline underwater] [ pumpkin seed recipe] [ bisexual mmf sex] [ strawberry gashes] [ my fair lady doll] [ jacket zara] [ 1996 gymnastics olympic team] [ saint george utah realtor] [ coldwell banker realty] [ adocommand parameters] [ used industrial paper shredder] [ oriental garden restaurant new york city] [ references] [ 98 sniper tippmann] [ 2006 maclaren stroller] [ mating horses] [ pennsic war 34] [ health product wholesale] [ engine rebuilder] [ opera fudge recipe] [ 8th grade] [ esthetician] [ stored procedure in sql server] [ riding arenas] [ mirrored desk] [ 99 nama allah] [ shotgun shooting supply] [ indigo girls tickets tahoe] [ phantom of the paradise] [ speigal] [ kia rio] [ philippine travel package] [ 61450] [ kim rucker] [ hamakua hilo hawaii real estate] [ www leo with you org] [ southwest airline ticket prices] [ so sincere with it] [ undertail kit] [ pepsi ice midwest overland park] [ sherborn ma public library] [ el ministry shaddai] [ guitar finger pick] [ bay of pig cuba] [ krystal steal mpegs] [ aerial photo] [ hollerback girl] [ air jordan] [ pussy licking gallery] [ all day hillsongs lyrics] [ adsl modem linux] [ cigar humidor] [ scooby doo games to play] [ unlocking nec e616v phone] [ shemale having sex with woman] [ apartment fire lansing] [ gorgeous women] [ atlanta apple service center] [ mercury gold amalgamation] [ scarecrow ideas] [ art graffiti sticker street] [ prince edward island book] [ game patches] [ santa cruz sentinel] [ hun page porn yellow] [ new england colonies] [ real naked women] [ performing arts medicine] [ smokey mountain real estate] [ blake shelton] [ wild animals] [ saul williams] [ new york supreme court appellate division first department] [ motorcycle blue book] [ classic ford mustang for sale] [ southwest airline baggage] [ vista] [ pablo picasso] [ arugula] [ sugar plum fairy nutcracker] [ home loan refinance] [ conan detective music] [ yurs funeral home st. charles] [ atlas road map of georgia] [ naked babysitters] [ stop ignoring here] [ motel coupons] [ angel devil drawing] [ terme di saturnia italy] [ caprice bourret gallery] [ frequency local police radio] [ fabric shower curtain] [ poteauok] [ peter jackson king kong blog] [ import tuner] [ reconcile accounts payable] [ snowmobile left hand throttle] [ geile omas] [ leadership training] [ northern california map] [ lun phudi story] [ prismacolor markers] [ seattle moving truck rental] [ new cholesterol medication] [ printout binder trolleys] [ 1080i hd tv] [ san diego swimming pool contractor] [ milk hill wiltshire] [ nasty granny sex] [ electrical hvac part system] [ lady diana] [ nissen surgery] [ josiah bartlett new hampshire] [ interratial] [ roma italy maps] [ rv cooktops] [ rolling hills prepatory school] [ price old silver coins] [ pinkseeker] [ gay couples galleries] [ hot girl pussy] [ quasimodo] [ mexican pussies] [ blowjob thumbnails] [] [ incubus logos] [ white noise for baby] [ jennifer lopez has a nice ass] [ furry pleasures] [ wedding flower] [ volvo brake light bulb] [ skull and bones] [ nirvana mp3] [ cum shot video] [ kansas powerball] [ raven symone fansite] [ grandma incest] [ school districts] [ 50 cents rap lyrics] [ famous breasts] [ natural nude pictures] [
ews.html software reviews] [ menstrual] [ watch face] [ the cheat] [ causes of gout] [ antique marv radio roth] [ nubile models] [ nevada and legislat and limited liability and co] [ antennas direct db8] [ christina aguleria nude] [ automotive painting touchup] [ fauxwood blinds] [ get it faster] [ new home utah] [ agamemnon] [ mens fetish clothes] [ larrys honda] [ young lolita angels] [ overdeveloped teenagers] [ curls] [ collar tags] [ hunting trips south dakota] [ mazda performance parts] [ remax hometown nj] [ essential functional skill] [ steve nash] [ housewives sexy homepages] [ las vegas suv limousine] [ trap muzik] [ teenage nympho] [ april cornell] [ vivian silverstone] [ atmospheric globe] [ poo panties] [ stone veneer] [ ketchum and associates] [ jabba licks leia] [ plus size prom gown evening gowns] [ state of oregon auctions] [ td bank] [ limos in chicago] [ cell phone reverse look up] [ ultima] [ knex dna models] [ dice] [ american equity underwriter] [ coffee kona] [ southestern louisiana university] [ baby shower clipart] [ jae p esperanza] [ girls uk] [ tennessee williams] [ uv air purifier] [ john marinelli] [ boob out] [ ip ligament] [ laura prepon gallery] [ play bingo win money] [ avid dv xpress pro] [
pics.htm clitoris pics] [ free games slots] [ suicide help] [ carrie lee] [ american football rule] [] [ thermomter] [ el tri] [ the war in vietnam] [ issac newton] [ anal fucking machines] [ nj sate] [ used car in wichita ks] [ refurbished precor ellipticals] [ nude kiddy] [ duplicating cheat for runescape] [ track lighting] [ pass drug test] [ james bond 007 agent under fire ps2 cheats] [ download weird ringtones] [ uhren de] [ xxx dbz] [ sonar night club vancouver] [ sexo fotos videos] [ rhubarb chutney recipe] [ womens leather handbags] [ lor n] [ house wife lonely] [ steven gerrard] [ online gambling site] [ ebay information product sell] [ female nude pictures] [ viper fish] [ lateral and vertical thinking] [ naked babys] [ ligion site] [ garden cart] [ soccer goal keeper] [ gynecological exam] [ kid goku] [ equity lines of credit] [ apsu online orientation] [ stretched on the rack] [ new orleans vacation rental] [ team running usa] [ petra verkaik mpegs] [ phone system maintenance] [ arlington animal hospital virginia] [ kids bowling ball] [ costa cruises] [ nm health insurance alliance] [ sketches drawings of angels] [ human skeleton pictures] [ ebony spanking] [ listen to your heart roxette music video] {| align=right
[[Image:Main-Eval-PG31-USB-Loaded.jpg|PG31 USB Dev Board]]
[[Image:Main-Eval-PG31-USB-Loaded.jpg|PG31 USB Dev Board]]
<b>Description:</b><br> You've probably heard about the CP210x USB ICs from Silicon Labs, now here's an application  
<b>Description:</b><br> You've probably heard about the CP210x USB ICs from Silicon Labs, now here's an application  

Revision as of 15:23, 24 December 2007

PG31 USB Dev Board

You've probably heard about the CP210x USB ICs from Silicon Labs, now here's an application 1000 that uses it. The CP2102 gives us 3V TTL to a VCP (virtual comm port) over USB as well as generating the 3.3V needed for the board.

In this project we demonstrate how to:

  • Setup a USB to Serial link
  • Use the CP2102 for 3.3V
  • Use a SMD 12mm battery holder


USB Connection

The CP2102 USB IC is fairly easy to use once you've plugged it down a couple times.

PG31 USB Connection

The USB connector has four pins : Vcc (*around* 5V), GND, D , D-. Tying these four connections to the CP2102 is easy enough.


There are a couple things to note. In this setup, we do not have any ESD protection or surge supression. We are quite possibly violating some USB standards. But does it work? Yep.

When you configure the CP2102 this way, it can source up to 100mA at 3.3V using its internal voltage regulator. This is perfect for our application as the PG31 needs ~40mA at 3.3V.

Note the TX pin on the CP2102 is an output and needs to be connected to the RX pin on the PG31. This screwed me up a few times.

The CP2102 has built-in cystal and eeprom. These means you need very few external components to get it working. You can even program in your own ID string so when you plug it onto your computer, it comes up with the name of your widget!

When the CP210x is attached to a computer (and it's soldered correctly) you will see windows hardware wizard request drivers. These drivers can be downloaded from SI Labs. You can also create your own signature drivers using some SI Labs software.

You can also program the internal EEPROM to reflect your own product ID and serial strings. This software is from SI Labs as well but I forget were - when someone finds it, post it here.

Once the drivers are installed, the CP210x will turn into a serial com port! Yes! It's weird to think about until you see it happen. So this USB dev board now acts like a com port on my computer. All I have to do is pass characters in and out COM 5 (for example) and I can do things over USB! No messy drivers, no protocols to think about, it's all done in the IC. All right!

One thing to note when you are using the CP210x ICs, the Linux community may scoff. SI Labs did a great job with the windows support, but a piss-poor job of opening the drivers for the open-source community. I'm not really a Linux person so it didn't effect me. But if your app needs linux connectivity, you may want to take a quick look for other potential ICs. Last I heard, there was good Linux support for the CP2102, but there was nothing for the CP2103 GPIO control...

One last con : The ICs come in QFN leadless package only. YES it can be soldered by hand, but you'll need some experience and/or some good hot-air soldering tools. I taught myself how to rework stuff using this IC. You really can't destroy it, but you can certainly delaminate (kill) the PCB if you heat it for excessive amounts of time. Don't 'not' create a PCB or a design because of silly SMD parts. They're not that hard to solder!

Battery Backup

12mm coin cell holder

If you're playing with GPS, you've got to have a battery backup. The 12mm coin cell lithium allows the PG31 (and many other GPS receivers) to retain the alamanac data. This small battery provides just enough juice for 3-5 years. By having alamanac data at power on, the GPS receiver will be able to do a warm lock instead of a cold lock. Cold locks take 1-2 minutes, warm locks, as little as 30 seconds. The alamanac data, in effect, allows the GPS receiver to 'guess' where it is in the world ("Last time I was on I was in Ohio, therefor, I will assume I'm near there").

If you're unfamiliar with Lithium Coin Cells - they come in a couple different sizes. I prefer 12mm just cause it's small but beefy enough to do most of the BBR (battery backed ram) that we need to support. The battery itself has a postive top (noted by the plus) and a ground on the bottom. You normally create a pad on the PCB for the ground and the coin cell holder is p 1000 ositive. We've learned the hard way that the bottom part of the cell is sometimes concave. This means that when you slide the coin cell onto the board, the concave ground part of the cell may not contact the PCB pad very well. If you're using a paste stencil, just leave a cutout for this pad. The extra paste will add 5-10 mils of solder to the pad. If you're solder the thing by hand, add a little blob of solder to this ground pad to give it some height. When you insert the battery, it should ride nicely on top of the ground pad blob.

PG31 Footprint


Now about the footprint for the PG31. Unless the manufacturer hands you a foorprint file or a simple, recommended FP in the datasheet, you're going to have to go it on your own. We took the PG31 and a pair of calipers and went at it. It can be extremely difficult the first time. This PG31 FP took me twice to get correct. Do the best you can and try to account for things like the antenna connector. The second rev FP, I forgot to account for the MMCX connector, I put the DB9 connector right up against the PG31, and Viola - useless PCB! a.k.a another coaster for my coffee cup. But once you've got the FP, you're good for all future projects using that device. Now you know when engs hate to change parts...

Final Layout


You can see the PCB layout is pretty straight forward. The 'solder jumpers' are a feature that SFE came up with to minimize our manufacturing time while allowing end users to populate the physical jumpers if they needed the ability to connect/disconnect a feature often and quickly. Most users just plug the PG31 onto their computer for quick evaluation. At some point, the CP2102 IC may need to be disconnected from the circuit so that an external micro or embedded system could be attached. If this is done back and forth often, the end user can clear the solder jumper with a swipe of the soldering iron, install a 2-pin header and a black plastic jumper. This now allows them to jumper/dejumper quickly and keeps us from having to solder the 2-pin headers into a board that may not need them.

Things to Improve

So that's pretty much it. The board works well, and assuming Laipac doesn't change their parts again, we will produce the board for some time.

We may consider migrating to a different USB IC someday but the CP2102 continues to be a really simple to use USB to UART IC.


PG31 USB Schematic

PG31-USB Protel File

PG31-USB Gerber Files

SFE Footprint Library

FP Name: PG31

Supplier Info: Spark Fun Electronics part # : Eval-PG31-USB
Single Piece Price : $29.95

Related Items:

Personal tools