EEVblog #642 – TI Connected Launchpad

hi today we’re going to take a look at the Texas Instruments tiva c series connected launchpad it’s one of these super cheap Internet of Things development boards now TI of course about 4 odd years ago or so released the original launch pad at 4.30 it was absolutely insane that price this one’s almost as insane it’s only 20 bucks or even from the likes of digi-key and other distributors absolutely incredible for what you’re getting here it must almost be cost price practically are they giving these things away unbelievable anyway so I get the part number right it’s got one of these ridiculously long part numbers is the ek tm4c one two nine four XL whoop-dee-doo I don’t have to give him such freaking long part numbers I don’t know anyway it’s the connected launchpad and it’s got a whole bunch of powerful stuff built in 120 megahertz 32-bit arm cortex-m 4 processor in it one mega flash memory 256 K of SRAM 6 K of e squared prom it’s got a 10100 Ethernet mac and phy on it and it’s got data protection CNC timers 212 bit to make sample for second ad C’s on it yeah that sounds impressive but I don’t know we’ll have to check the datasheet for that because might be 12 bits but what’s the effective number of bits how good is it really I don’t know usually the ones built into these micros aren’t that crash off but still 12 bit ADC at to make samples per second fantastic it’s got pwms it’s got USB serial comms it’s got a key all 32 bit code limited C compiler as well as the IAR 32 k c compiler as well so yet limited 32k but can probably do a whole bunch of useful stuff in that it comes with a starter guide and apparently pre-programmed for with an Internet of Things application so you can just hook it up supposedly out of the box and it just works as an Internet of Things demo will it I don’t know let’s try it so what do we get in the box well let’s have a look we get a quick start guide but you take a look up we get the board SD rap for your protection and we get one of these ridiculous badly designed pull ethernet cables I hate these things under there you know these kind of sort of convenient for travel and things like that otherwise pain the ask and a yet another microUSB cables if I didn’t already have enough and you get a relatively fair amount here for your twenty bucks we’ve got the main TI processor of course that’s the arm cortex-m fort that’s actually what you’re paying for we’ve got ourselves a little light pulse transformer here for your 10100 Ethernet of course and we’ve got a couple of us which is around here doing various things couple of jumpers for various site configuration stuff and you also get a debug and slash a programming interface over here so you got yourself a little debug head up tiny little pitch and you’ve got two booster pack connections here that’s their term for you know the add-on boards and they have a whole bunch I like how they’ve labeled the signals on the back there that’s really nice and we got ourselves a MAC address and supposedly comes already pre-configured as I said with that Internet of Things applications well it seems the QuickStart guide doesn’t entirely suck um we’ve got a board overview here and we got ourselves the debug and power ports powered from the USB port here it’s got like no tournament doesn’t look like it’s got any terminal connections for external power you have to sort of use that micro USB I think although it does have a power select jumper here so I’m not sure what’s going on there I don’t see any other big tabs oh that’s right you can get a battery pack attachment for the booster so you can come in your power can come in via the booster connectors apparently so that’s probably what that’s switching there we couple have got a couple of user LEDs and iOS and user switches and wake and reset switch and yeah that’s about all not a huge amount on there it’s designed of course to have all the plug-in booster packs I got ourselves a pretty funky looking I owe map here for the two booster pack connectors it’s kind of weird how they’ve sort of like staggered them Oh soon that that is the other side of that connector there and uh yeah like you know I don’t know how does that sort of match up to that kind of thing I’ve got to assume that sort of that one there is that row there and that calm yet that one’s that one and blurt so on so anyway I that wasn’t great would it be nice to have a photo in there but anyway um here we go here’s our our basic steps for

connecting up our Internet of Things demo I’m going to follow through those and see if it works or will it be a donkey just a quick look at these jumpers here I do like how they’ve labeled those there we go power select power can come from the booster pack USB on-the-go or the in circuit debugger you generally wouldn’t pair it from the in circuit debugger in that system use of course but yeah that’s really nice 3.3 volt jumper for the microcontroller here that’s nice assuming that that disconnects all the power from there that’s a really useful because then you can put your current meter in there or your micro current whatever and measure your current consumption if you CPU so that could be really nice I’ve got another 3.3 volt jumper over here I’m not sure what that one’s actually doing but yeah it’s handy to be are we getting there and measure your power consumption on these development boards and just a quick one here is an example of where burden voltage on your multimeter to measure current causes an issue let’s actually probe this thing I’ve taken the jumper off okay and watch the LEDs down there you’ll see that that lead is it barely like it’s not functioning it’s not pairing up as it should right but if I connect it over to the amps jack here and do the same thing bingo it powers up no problems whatsoever and starts to operate because it obviously the burden voltage of the meter was too high and it was dropping the voltage to the microcontroller couldn’t operate properly at that particular current and we should switch over to the ants range and everything’s hunky-dory and that’s the leads that I expect when it actually runs the thing so there you go that’s just a little example of burn voltage today okay step number one go to TI EXO site comm RT I have partnered with EXO site I don’t think I’d heard of EXO site before but yet another one of the countless internet of things like online cloud type services company that are popping up to get all your stuff connected anyway they’ve got a couple of tutorials and things like that here but we’ve got to sign up create an account here so I wait boy with the details will come back alright I created an account and the stupid thing asks you to put in like a really secure password I put in like my standard just dumbass password for sites like this and it just wouldn’t accept they’re not secure enough screw you and I hate that sort of crap anyway up yeah logged in it gave me the email thing I had to verify my email but yeah and it gives you apparently gives you a 30 free SMS test messages or something you get the EXO site system can apparently send you SMS messages when your data from this device beats certain conditions and stuff like that to alert you when you get 30 for free and after that I don’t know how much it cost anyway alright here we go we’re going to click here to add a new device to our portal and let’s see here we go these are all their can at launch pay connected Launchpad there we go that ridiculous part number and that’s the one I want too yep continue set it up enter your MAC address and here we go we’ve got to give it a name I’m going to call it Bruce good on your Bruce and we’re in Sydney Australia not Austria let’s go through and lo is successfully enabled with the cik whatever the hell that is your device is connected to the eco site platform within 24 hours provision request what’s that garbage ah yeah whatever let me play with it ad device no that’s it already done so let’s go home and then we go Bruce there’s Bruce active on active event nothing I guess now I have to plug it in it’s all plugged in I only have one USB port in fact I have to take off my little bluetooth dongle didn’t have any and bloody so many USB connected bloody devices and only a one spare port left on my Ethernet switch as well so it’s all plugged in let’s see if the sucker works righty-o come on Bruce you can do it mate here we go let’s click on Bruce and we’re in we’re in online it’s been online tight okay it’s got an online counter that’s pretty good junction temperature of the device of the presumably like it’s just got an on trend on cheaper transistor you know PN Junction silicon diode temperature sensor they’re pretty crude but they do the job and two minutes and eight seconds has been online actually see if I can heat up that chip see if it changes hang on I’ll put my finger on it

I got my finger on it and we’ve got a graph of the junction temperature there and no no I’ve got a bit of noise on that you know in fact we’ve got a lot of noise on that thing anyway that’s the junction temperature and that’s all it’s displaying at the moment next waiting for device hmm oh there you go there are 989 launch pads connected around the world look at that any in Australia IIT tell you what am I the only one in Sydney you didn’t know there’s two there’s two can you believe it two in Sydney one there and one in glebe somebody in gleb’s got one good on you and I mean well I I just put Sydney as my supper I didn’t know that you could actually put in a that’s right it did ask for a you could put in an exact GPS location of the thing so I could go in there and edit my account I’m sure an update that but I just put in a generic Sydney so it’s just showing it’s smack in the middle of one of the main arterial roads leading to the Sydney Harbour Bridge there’s a Sydney Harbour Bridge for those who don’t geographically know Sydney the Opera House is just there and yep that’s smack on one of the one of the overpasses they’re leading to the Harbour Bridge awesome and here we go yes I do have the launch pad under my desk here because of the tiny short little USB cable provided and stuck in the back of my machine and please forgive the crudity of that video quality anyway look I cannot turn the lead that they were both on before and turn them off they should be off I can’t see it it’s actually under my desk but I have no reason to believe that is not that LED is not switching off and on there we go I’ll switch it on again Andrew that was terribly exciting what happens if we touch the switch anything nope zip and if we press the buttons here there we go let’s have a look three button pushes and the other one let’s wait it takes a while for that I Canada update I think yeah there we go it does take a while so I’m going to press those really quick and see if it dart buffers those button presses and then so I’m going to do the one on the left here I’m going to hit it three times real quick one two three will it jump up to ten let’s find out it did there you go okay so that’s not bad at all so therefore I properly debounce those end and actually buffered those I’m not sure how quickly it updates the probably you know like it polls it probably every second or something polls the board that’s typical for these Internet of Things devices anyway so let’s check out a few other things on here I’m going gone down to the portal art menu down here on the left-hand side and here’s my portal results summary and yet there’s no SMS limit I was wrong on that I didn’t completely read the email to get your 30 SMS free SMS things you’ve got to fill out a stupid freaking survey unbelievable anyway it can send ten emails daily as part of the service for free I guess but I don’t know about the prices and the plans for this thing I don’t know check that out for yourself and shares we’re only allowed a certain number of you know these things based on our current plan but anyway it looked portal rolls it looks like you can enter a view you can enter viewers managers presumably it is public viewable I’ve got to set that up if it is I’ll link it in down below if you can actually see and you can see the I’ll leave it running and you’ll be able to see my connected Launchpad I’ll leave it up there for like leave it connected for the next couple of days or something like that unless I can find something useful for it but there you go you can invite users and have them hook up and role of a manager or viewer I don’t know exactly what’s going on there but it sounds quite comprehensive then we’ve got some scripts let’s go in here and check this out Bruce alert manager handler waiting waiting for something okay well I guess we can set up scripts for all your script kiddies out there fantastic I’m sure it’s actually quite quite powerful and it’s um it’s all TI branded here of course but it’s not actually using T is the website it’s actually using EXO side of course it’s just a subdomain there on the EXO site website so this all is back end all this back end front-end stuff is all powered by EXO site so presumably you don’t need a Texas Instruments

device to use EXO site you can hook up any internet of devices thing that you want there and so what I’m going to do is I’m going to um I might have to try and get fill out this stupid survey to get my free SMS is because I want to like push the button on this thing and set it up and then you know get it to send me an SMS based on this is a little current data Junction game state whatever that is oh yeah by the way when I signed up for this thing it’ll happen to choose the time zone fantastic but it did not have bloody Sydney listed there me all that was bloody Brisbane or Perth or something like that yeah correct time zone but ah give me a break don’t like bleh Brisbane bloody Queenslanders well well look what we have here what the hell is this console get has stopped working what the hell is the comms surrogate close the program shockwave flesh may be busy are what the hell unbelievable continue no it’s just it’s crashed unbelievable what I have a garbage what the hell’s going on well maybe I don’t have the latest Shockwave Flash plugin I’m sure I updated that the other bloody week when it popped up and annoyed me about it this is just ah alright it just spat the dummy and we’re back I don’t know what happened there but check check this out if we click on Junction temperature look what’s pops up here the graph of the junction temperature this looks really quite powerful and there’s our device Bruce and you can do calculations and all sorts of stuff data I am what I you would have to spend hours to sit down and try and study exactly what this EXO site thing’s capable of but this looks pretty powerful and all the data logging stuff is there delete data source share data so I can share it with people or download it presumably that’s really quite neat and same thing will happen if I click on the lead one no doubt yep so we can get data for the lead see how many times the leads turned off and on or the user switch or anything else that you want to set up not bad now I’ve actually come back the next day I shut down my machine well I didn’t shut it down overnight but I put it to sleep mode as I normally do overnight so I came came back today and look it’s now offline I had to log back in it had sort of logged me out from the EXO site thing but it says Bruce’s off line here and like I don’t know what the deal is it hasn’t like automatically free refresh my board is still powered up it’s still plugged into my Ethernet connection by the way my internet connection was shut down overnight though because my ISP was doing an upgrade thing so maybe that has something to do with it but geez I would have expected it to automatically reconnect anyway there are flashing lights still on the board and is powered up I haven’t physically touched it since then so not sure what’s going on there at all and the strange part here is on this main home screen here look it says active on active event no so I you assumed I thought that active on would have meant that it’s it’s physically online but it’s not look status offline all I’m going to do is well repower the board and see what happens here we go there we go I’ve repowered the board and by the way I’m still getting that com2 sorry good error or whatever it damn well is here we go yep it’s appeared online so has the board done something weird when it lost the internet connection has it lost locked up or something like that perhaps because I definitely do know my internet connection went down last night so but geez you’d expect it to be robust enough to to handle that sort of thing and recover that’s what you need from Internet of Things anyway um I don’t know need to hear back on that whether that’s a bug or not all right now we’re going to assume that the air at that virtual comm error message that keeps are popping up is due to the fact that I haven’t installed the drivers for the virtual comm serial port so it tells you that in the QuickStart well it tells you to download this in the QuickStart guide so I will and I’ll be back ah I really hate drivers like this that just come in a zip file oh you’ve gotta unzip them and then it’s just the driver files it doesn’t actually give like an install or anything like that so I’ve got to go through the manual process of bloody installing the driver what a pain in the ass okay so what I’m going to do now is going to try and add an event here so if I click add an event I want to get this thing to email me when I push the button okay something incredibly simple like that I can’t get the SMS to work yet because I filled in

that survey thing and you have to wait like 20 four to 48 hours before your credits come through on your SMS stuff and goodness anyway so use a switch one so let’s see what we can do with users which one here event name you know we’ll just call it switch or something like that and I don’t know simple yeah time out okay that’s not bad you can count after a certain number of counts that’s pretty good you can do if then until sit right okay that’s pretty good that looks really quite nice I like that interface all right what we’ve got here is we’ve set up that event now it separates events from alerts here and that makes sense really so what we’ve done is we’ve set up this event called switch which all it does very simple that if the if I press the switch I just guessed that the constant was one here and I was correct and then it basically you can do more complex out constructs than that but I’ve just set that and you can see I’ve already pressed the switch once and it has detected it so one occurrence in the last seven days so now we should be able to set up an email alert or some other alert here that is then associated with that event called switch let’s try it so let’s do that ad alert here reference event source and by the way I haven’t read any documentation for any of this I’m just winging this first-time user stuff so switch on Bruce if we had more than one event it would have showed up if we had more than one event on more than one device then presumably they would all show up there so the switch there we go let’s alert name Dave switch email and alert interval in seconds no-repeat okay email so the alert where email send David eevblog and we’ll just call it Bruce switch there we go and submit and now I’m going to try that and see if that you know I enter a new murkrow Alert numerical value hang on whoa alert interval zero okay forced to put that in there we go submit so now should email me that if I push the button whoo and I’ll tell you what these comms sorry get error message is getting really annoying they keep popping up like every couple of minutes infuriating anyway I’m going to push the button reaching under the desk here we go I pushed the button it could take a second a couple of seconds to update that because it’s not a push I don’t think it’s a push thing I think it’s a hold I’m not sure occurrences come on come on don’t make a fool out of me come on you can do it you can do it no do I have to read it popped up much quicker than this last time it really did it popped up within a few seconds so what why not sure what’s going on there where it might have been that common surrogate error message bloody thing I’ll just refresh the entire page and not false actia what’s going on what’s going on I don’t know false as in I don’t get it well if I go back into the event here it now knows that it’s associated with this alert here so that’s rather nice but I have no idea why it’s going false and I’m pressing the switch and it’s not showing up I don’t know what I have to do reboot the bloody board again okay now what I’ve done is I just deleted this entire event and started from scratch again I couldn’t figure it out so now it’s active true and I’m pretty well look it’s got one occurrence already up so I haven’t pushed it let’s try it again anyway and I set it and it deleted the alert as well the associated alert so anyway I’ve reset it up let me push the button there we go I just pushed it and will it pop-up it should because it’s active right so it did last time yet no nothing yet ah come on I’m obviously doing something stupid right it’s got to be me it’s got to be a peb CAC now I tried looking at the various tutorials and while the tutorial videos and stuff like that and it basically stops at that main dashboard type screen it doesn’t go into the events and how to actually script those and things like that but I’m into the device information screen here and I think I’ve got to figured it out look down here use a switch number one I’ve pressed it twice and sure enough it’s like a counter

thing it’s not it doesn’t seem to be well that’s the actual value right let me press it again I have to refresh here but it should pop up as three there it is so when I maybe that’s the reason why that event thing is maybe caught up in a loop or something like that that’s the only thing I can think of here if I go into events over here because that number is no longer I thought I’d go from one when it’s pushed to zero back down to zero but maybe it’s not like that value there so I don’t know oh all right now I just got switched to to work I set up a second one and I just pressed it and sure enough it did come up live let’s see what happens if I press it again here we go I’ve pressed it a second time will it actually come up with a second occurrence there no let me refresh it not now it’s active it’s now it’s gone false to get what the hell yeah okay that’s the event I so it’s got to be that number not going back to zero because look if comparison is true then enter event okay until comparison is not true I expect it to go back to zero when you release the switch I’ve got to be doing something dumb surely but I don’t know I’ve had a look at the Paige and I’ve looked at the FAQ and I’ve had a look at a few things his demo here which doesn’t show anything and he goes the dashboard I don’t know I’m going to give up anyway on the positive side here look I did actually get the email in my inbox I did get one an hour ago which was the original one then I deleted that why deleted that event and item and then I created another one I had hollow days so it does actually work it is sending the email but bug it if I can figure out how to ah why it’s not doing what look here we go something going on here but why it’s not doing what I expect I got no idea all right on the positive side here after installing two different drivers here well manually two different ones I finally got the stellaris virtual serial port it didn’t install first it installed these ones first and then had to install this separately anyway there’s a virtual serial port which looks up to the code already running inside the launchpad and here you go I am connected 115 cabled and there you go we can play that tic-tac-toe game so tic-tac-toe we’re running play locally play online there you go so hopefully I remote user starts so I’m going to do that and the remote user can start waiting for the remote player to see if we can access presumably it’s accessing the exo site server and it’s waiting it’s thinking I don’t know so we can leave that off screen and we can go in here and we can right here we go something something happened something happened to Bruce Wayne at night still waiting for a remote player so anyway that is supposed to pop up here and oh there we go that was me ah there you go I didn’t put the X in the center square or no fail and in two row there we go okay so yeah I can go like one and then one and boom it should wait in for the revoke players should my one should pop up here although I’ve got to manually refresh that there we go a popped up so it works so anyway I think I need to play around with this thing a lot more and maybe try and find some tutorials to figure out you know exactly how all this online stuff works I can actually see the power in this EXO site stuffy there there is quite a bit in here which really excites me in terms of you know being able to configure alerts and events and and do stuff like that and I would obviously have to install the tools the TI tools all the compiles and stuff later to look at the source code to how easy that is to modify and then create your own application of course this is just an internet of things demo but if you wanted your own application to be Internet connected enabled I’m sure it’s

a fair bit more work than this so but I do kind of see the value in in a lot of the powering a lot of all this but I’ve had a lot of issues quite a few issues with this thing and maybe it is a peb kak error with stupid me but hey you know I’m trying to use this thing out of the box I followed the QuickStart guide and I’m getting constant errors popping up and all sorts of things and just this stuff like just simple switch events not working as I’d expect them to but the email alerts seem to work that you know the remote tic-tac-toe game worked and all that sort of jazz so I’d yeah I don’t know I probably going to call it quits he has probably been long enough to take me another hour a couple of hours to install the C compilers and everything else and look through the code and try and modify it and do all that sort of example but hey you know it’s worth having to play around yourself I mean for 20 bucks it’s only going to cost you 20 bucks and your time to have a play around with this thing so I don’t know it’s it’s not too bad but yeah I think there’s probably a few I suspect there’s a few bugs in here and the out-of-the-box user experiences it kind of worked but then quite a few issues so I don’t take that what you will that’s a look at trying to get this Internet of Things 20 buck in and editing’s Launchpad working I hope you found it moderately useful it wasn’t a tutorial by any stretch it was just me using it straight out of the box and following the quick start and start guide so you could probably expect a similar thing maybe you won’t have the same hassles I will but yeah does kind of work anyway hope you enjoyed it if you want to discuss it jumping over to the EEV blog forum catch you next time whoa hang on one last thing um you know how I mentioned the ADC at the start of this well let’s have a look at the datasheet brief look look at this top left corner that page 1861 of almost nine a nineteen hundred page datasheet for this chip do you believe it anyway it has a whole ADC section sure you can get a short-form version of the datasheet but this is the full thing 1900 pages that’s FPGA like data sheets that’s just madness but such is the power and flexibility of these modern micros they cover absolutely everything but ah geez anyway we’ve got all the data we could possibly need for the ADC down here by the looks of it and let’s have a look down look at the input leakage current there two micro amps maximum analog source resistance 500 ohms so there you go that’s quite high you want to drive this with a low impedance our source to minimize your errors that’s for sure a DC conversion clock runs at 16 megahertz 1 Meg sample per second rate they claim to I thought as their top-level r-spec there so I’m not sure what’s going on there whether or not they’re claiming the second channel or not and maybe could interleave them but yeah conversion time 1 microsecond sample time resolution 12 bits integral non-linearity plus minus point 1 point 5 or 3 least significant bits maximum differential non-linearity you know it’s an okay ADC for a twelve bidder so it’s probably doing offset error there we go there’s your fifteen least significant bits offset error their gain error thirty least significant bit sir there you go so yeah you know it starts to get a bit ordinary and they should signal to noise ratio stuff and you can go out and compare this with like over five or ten dollar ADC like 12 bit 80s a real proper one that’s designed for performance and linearity and you know no errors and everything else so I recommend you go get and look at all the traps for young players here look at all these little footnotes here you’ve got to look out so you’re going to read all these two capacitors in parallel blah not valid here blah blah blah with signal common ah there you go got to be careful you got to read all the fine print they’re nasty ah here we go at to make samples per second there you go so it looks like you can actually they specified at one Meg sample and to make sample so you probably expect worse specs at 2 Meg sample there we go 32 megahertz clock there and yeah okay and no similar similar specs I think so there you go anyway I highly recommend you go in and compare that to a real ADC in quote marks and see the performance

differences you you