RobB 0 Posted August 4, 2014 Share Posted August 4, 2014 Hi y'all, (First post newbie alert) I'm loving playing with my Launchpads and am currently working on some robotics projects, including designing an intelligent motor controller that uses I2C interfacing. Well, as these things go, the I2C communications didn't work right off and I was frustrated by my lack of a logic analyzer, so I decided to throw together an MSP430G2553-only logic analyzer capture system that communicates to existing SUMP clients. It works well considering a one-weekend investment of time and I'm learning lots. It can collect 390 samples, with 8 probes, at a maximum sample rate of 1 MHz and serviceable triggering modes. (I'm hoping to optionally raise the number of samples by reducing the number of probes, reducing the sample rate, and bit-packing the data; I guess I'll eventually add an external memory to get past the 512 byte RAM limit!). Anyway -- to my question: I'd like to get this logic analyzer off my Launchpad and make it a semi-permanent unit for my use. It's no problem to make the MSP430G2553 standalone, but I'm still tied to the Launchpad for the USB-Serial communications. What's my simplest way forward? Here are the options (and disadvantages) I'm aware of: 1. Buy the FTDI interface chip and learn the whole new world of designing and making PC boards and hand-soldering small chips (lots of new things to learn, so no small project, but maybe I should go ahead and bite the bullet?) 2. Buy the FTDI interface chip and a breakout board so that I can build the unit using 0.1" prototyping methods I'm comfortable with (starts to get expensive compared with just buying another Launchpad) 3. Just use a Launchpad (limits the baud rate to 9600 and keeps me confused when I have three Launchpads plugged into my system [i2C master, I2C slave, logic analyzer] that I have to keep straight in CCS]) 4. ??? What's the simple way forward? I feel like I must be missing something. Is there an MSP430 with built-in USB communications? Is there an inexpensive DIP UART-to-USB solution? Is there a way to make a Launchpad identify itself differently to the host computer so that I can make the logic analyzer obvious in my list of attached devices? Thanks for your suggestions! Rob Quote Link to post Share on other sites
cubeberg 540 Posted August 4, 2014 Share Posted August 4, 2014 There is a bit-bang USB project for the 2553, but it would probably mess up whatever else you were trying to run. Have you looked at the 5529 launchpad? It has built-in USB. Otherwise you will have to go with an extra chip like the G series LP does (TIUSB). Quote Link to post Share on other sites
colotron 5 Posted August 4, 2014 Share Posted August 4, 2014 What about using an usb-to-serial cable and work with RS-232 like the old days? Quote Link to post Share on other sites
oPossum 1,083 Posted August 4, 2014 Share Posted August 4, 2014 Get a FDTI board. Just do it. You will find many uses for it and soon have several. 6 channel MSP430 logic analyzer with 256k sample memory: http://forum.43oh.com/topic/2480-6-channel-logic-analyzer/ RobB 1 Quote Link to post Share on other sites
RobB 0 Posted August 4, 2014 Author Share Posted August 4, 2014 Get a FDTI board. Just do it. You will find many uses for it and soon have several. 6 channel MSP430 logic analyzer with 256k sample memory: http://forum.43oh.com/topic/2480-6-channel-logic-analyzer/ Thanks, oPossum. I did see your very nice design (one of very many of yours!) and would love to do that as the next step. I was just seeing what I could do with no additional parts since I'd have to order the RAM to build yours...my stash is not yet well-stocked! As for the FDTI board, am I missing an important difference between the $15 SparkFun board and the cheap slow-boat-from-China version (http://www.ebay.com/itm/FT232RL-USB-Serial-adapter-module-USB-RS232-Max232-Arduino-download-/310510484589) ? (I'm still trying to fly under the radar of our hobby budget here, so if I'm going to buy a handful of these things....). And is there an issue with level-shifting for the MSP430 voltage? There is a bit-bang USB project for the 2553, but it would probably mess up whatever else you were trying to run. Have you looked at the 5529 launchpad? It has built-in USB. Otherwise you will have to go with an extra chip like the G series LP does (TIUSB). My current design doesn't have to do anything else while it's uploading the data, so I'm not at all against bit-banging, in principle. The things I found quickly all pointed at implementing an HID device rather than a COM port. Has anyone made the leap to connecting to a COM driver? thanks! Rob Quote Link to post Share on other sites
roadrunner84 466 Posted August 5, 2014 Share Posted August 5, 2014 You could also buy an FTDI cable, they have 0.1" 1x6 headers attached to connect the 3.3V serial signals to the FTDI chip that is molded inside the USB connector. Another option is to buy a piece of SMT prototyping board, those have pads connected to SOIC footprints already, you could use a little piece and reuse the rest of it for other projects including SMD components. RobB 1 Quote Link to post Share on other sites
jazz 209 Posted August 5, 2014 Share Posted August 5, 2014 There is also PL2303HXD, up to 12 Mbps, works with any BR. http://forum.43oh.com/topic/3350-msp430f550x-based-usb-uart-bridge Quote Link to post Share on other sites
cubeberg 540 Posted August 5, 2014 Share Posted August 5, 2014 There is also PL2303HXD, up to 12 Mbps, works with any BR. http://forum.43oh.com/topic/3350-msp430f550x-based-usb-uart-bridge Isn't support for that on windows 8 pretty buggy? Quote Link to post Share on other sites
jazz 209 Posted August 5, 2014 Share Posted August 5, 2014 Isn't support for that on windows 8 pretty buggy? Have no idea about PL2303HXD and Win8 combination. AFAIK, FTDI have more stable drivers than Prolific, but it is limited to 1 Mbps (or little more) and have only one (or few) free slot(s) for non-standard BR. Quote Link to post Share on other sites
oPossum 1,083 Posted August 5, 2014 Share Posted August 5, 2014 The FTDI is capable of jitter free operation at 3,000,000 / N bps. It can use fractional division for operation at more bit rates, but that causes some jitter, so I don't recommend it. It has no special knowledge of 'standard' bit rates like some other chips - it is a simple divider. So the highest reliable bit rates for the FTDI chips are 1.5M, 1M, 750k, 600k, 500k, etc... roadrunner84 1 Quote Link to post Share on other sites
zeke 693 Posted August 5, 2014 Share Posted August 5, 2014 I am in the process of developing two different RELaunchPads that might be of interest to you. Here is the thread on the G2 RE-LaunchPad. It has a CP2102 USB UART which is a rock solid device. And here is the thread on the F5529 RE-LaunchPad. Do any of these designs meet your needs? Quote Link to post Share on other sites
SixSixSevenSeven 23 Posted August 5, 2014 Share Posted August 5, 2014 The CH340 is an easier package to solder than the FTDI USB-serial converters if you were to go the custom PCB route. Haven't tried one myself, apparently windows 8 will auto install the driver, its already working on most linux distros and drivers are around somewhere for windows 7 and below, no idea about mac support. In my experience the PL2303s are not worth it. The ones hooked up the the cisco routers at uni seem to desynchronise their baud rate over time, the machines with FTDI adaptor cables don't have the same issue, driver support for them is generally terrible. As soon as a fresh generation of chips is introduced and a new OS version comes along they effectively discontinue all previous revisions, not just a case of enabling or disabling driver signing to get them working on windows 8, all but the very most recent version of the prolific PL2303 do not function, some of the older revisions also don't function on windows 7 or OSX. Oh, I did run the FTDI at 921600 baud once without issue but wasnt for a particularly long time. Quote Link to post Share on other sites
zborgerd 62 Posted August 6, 2014 Share Posted August 6, 2014 This thing works for under $7 shipped. http://www.amazon.com/gp/product/B009T2ZR6W (CP2102 module). You can solder a pad to provide 3.3VCC (defaults to 5V) to power the MSP430. I used it a few days ago for this task (created a UART without using the Launchpad's built-in lines) on Ubuntu Linux but I hear that the drivers are fine on Linux as well. I have two of these. One is set to the default 5V on VCC and another that I've set to 3.3V. RobB 1 Quote Link to post Share on other sites
RobB 0 Posted August 6, 2014 Author Share Posted August 6, 2014 This thing works for under $7 shipped. http://www.amazon.com/gp/product/B009T2ZR6W (CP2102 module). You can solder a pad to provide 3.3VCC (defaults to 5V) to power the MSP430. I used it a few days ago for this task (created a UART without using the Launchpad's built-in lines) on Ubuntu Linux but I hear that the drivers are fine on Linux as well. I have two of these. One is set to the default 5V on VCC and another that I've set to 3.3V. Thanks for the suggestion! I was looking at things of this sort and landed on this one: http://www.ebay.com/itm/151369386564 so that I can use my existing USB cables and because it has the FTDI chip (or at least it says it does!). But it's good to know that the CP2102 is a good option, so I'll keep this one in mind if I have any trouble. --Rob Quote Link to post Share on other sites
SixSixSevenSeven 23 Posted August 6, 2014 Share Posted August 6, 2014 Thanks for the suggestion! I was looking at things of this sort and landed on this one: http://www.ebay.com/itm/151369386564 so that I can use my existing USB cables and because it has the FTDI chip (or at least it says it does!). But it's good to know that the CP2102 is a good option, so I'll keep this one in mind if I have any trouble. --Rob I've had some ebay FTDI chips before, there is a large market in chinese factories faking them, none have lasted more than 2 weeks in my possession before failing Quote Link to post Share on other sites
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