guybarash 0 Posted November 12, 2014 Share Posted November 12, 2014 hi, i'm a proud owner of a launchpad Msp430F5529, and i'm trying to power it up with an external 5v power supply. if i connect the device to my computer - it works. i connect the 5v network it doesn't work. i connect the 3v3 network to a 3v3 power supply - it works. i connect the launchpad to a galaxy cell-phone charger - still , no work. the 5v , 3v3 ang GND jumpers are connected. when i connect the 5v power supply i measured the voltage on the 3v3 jumper - nothing there. i assume the computer is activating the dc-dc convertor which is not powered when no computer connection exits , if thats the case , how can i work it to work ? if i'm wrong, what is the problem? thank you Quote Link to post Share on other sites
cde 334 Posted November 12, 2014 Share Posted November 12, 2014 Edit: I was thinking the wrong thing. Have you measured the 5v VUSB when connected to the charger? Quote Link to post Share on other sites
guybarash 0 Posted November 12, 2014 Author Share Posted November 12, 2014 when connecting to charger the 5v and the 3v shows nothing (not exactly 0 , around 30 miliVolt). but the ground pins are excatly 0. i have 2 launchped (same module) . both show same result. Quote Link to post Share on other sites
cde 334 Posted November 12, 2014 Share Posted November 12, 2014 According to http://43oh.com/2013/09/msp430f2559-launchpad-first-impressions/ you can't. TI has a faq that says it's because powering the usb devices before the usb hub is powered up is bad. If you ever had a cheap Chinese usb hub you know that's not reality. The usb hub controls a pair of usb power switches. If the hub doesn't enumerate, the switches aren't enabled. Instead of adding a jumper or a switch or something, TI forces you to use an external 5 and/or 3.6 supply. You can fix this with some soldering, I'll look at the schematic when I can Quote Link to post Share on other sites
cde 334 Posted November 12, 2014 Share Posted November 12, 2014 Double post ignore Quote Link to post Share on other sites
cde 334 Posted November 12, 2014 Share Posted November 12, 2014 Do your LaunchPads say Rev 1.4 or 1.5? Rev 1.4 or 1.2 had the usb power switch that prevented using a USB supply, 1.5 does not and should work just fine from a usb charger or from putting 5v at the 5v header at the bottom. Quote Link to post Share on other sites
guybarash 0 Posted November 12, 2014 Author Share Posted November 12, 2014 i have the Rev 1.4 . the usb power supply is not such an issue for me, but the external power supply using the pins is. if i connect a 3v3 + GND to the 3v3 network my device works just fine , but if i supply 5v directly to the 5v pin - nothing happens, the dc-dc doesn't either gets power (which is odd, there is power in the 5v jumper) , or it does get power but doesn't convert (the 3v3 jumper isn't getting power). if i could either connect the device directly to a 5v or insert a 5v supply through USB both will be Okay (preferably directly to the pins). does that require soldering as well? Quote Link to post Share on other sites
cde 334 Posted November 12, 2014 Share Posted November 12, 2014 See http://forum.43oh.com/topic/5215-how-to-power-f5529-with-usb-power-supply/?p=45889 for instructions on how to cut a single trace and solder another in order to fix this on your Rev 1.4 boards. Quote Link to post Share on other sites
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