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UCM Breakout board ... not very impressed!


I got a couple of Breakout UCM board. I’m bit amazed to read:

The Breakout Board also provides a USB connector for connecting to a host computer. It does not, however, have a 3.3 volt regulator. 5 volts from the USB connector is available on a pad on the board (5V USB). You can wire your own regulator between this pad and the 3V3 pad to power this board over USB. These pads and a ground (GND) pad are conveniently located in close proximity at one corner of the board (see picture below).

for a € 44 option (the same price as a Raspberry 3+) it doesn’t supply neither a simple regulator for 3.3V rail !.

I’m lucky enough to have old G400D Hdr boards…


It is made to build commercial prototypes where the developer has the option of using whatever power source they prefer.


Let me further explain. In some cases, you may need to add a larger display that requires a lot of power. In others, you may need a battery operated low power setup. It would be very difficult to select a one regulator to for every need.

Regulators are cheap and we have plenty in house. Cost is not the reason for not adding one.

I hope this clears it up some more.


@Gus_Issa, I perfectly understand your point of view … no discussion about that because it makes lot of sense.

I’m just saying that a self contained UCM module power supply (5V+3.3V), with an fast-and-easy 3 pin jumper to disable it, can simpify a lot the life of many maker/developers for prototyping in most situations. That said, it can be used as is, with a bit of wiring … :thinking:

Chinese come in help in this case …


I love those breadboard power supplies. I am glad you have one of them.


Yes, but be careful. I bought six of those same ones and found the output to have a LOT of ripple, and weak (below-spec) current output - enough to keep an ST SPWF04SA from booting. There are also widespread reports of them leaking the ‘DC IN’ current directly to the 3v3 output, which will make for a bad day for all your components. They are cheap, but under-filtered and under-powered in my experience. At very least, I would test each one out-of-circuit before use.


You are absolutely right, I bought 10 PCs and 3 are faulty. Mostly are out of specs about current and they make problems to displays ( 4d system for example). I find that with 9v input they are acceptable for small MCU boards…


@dobova , @Gus_Issa, @mcalsyn

please can you speak in our mortal languages (i am not proficient on electronic like you) since i am just an software developer so in this case @dobova has right,beause for me will be very hard to know what to and how to do because i missing right connector to use directly so in this case i will need to ask an electronics engineer what next step and who can do that…(but thanx god i am using always 3.3v / 5v shift level converter which have 5v input and 3.3v/5v output but i can never be able to find problem regards power since i dont know did level converter have right output ?


@valon_hoti_gmail_com here we are talking about power supplies, not level shift beetween data lines.
The UCM breakout board doesn’t provide a ready-to-go power supplies for the ucm module. This means that usb connection doesn’t provide a 3.3v (5v is directly usable from usb) and this means that you need an external circuit with a 3.3v regulator to supply needed voltage to the module uc5550,uc2550 or g400.
So the problem can be solved using the breadboard power supplies as shown in the image, that can feed the 3.3v to the module.


i know your are not talking for level shift but for power supply , but as you mentioned you have problem with such power supply boards when you got 10 and 3 was faulty same situation is with me i’ve got 5 and 5 of them was faulty so pushed me to find a way of usage of 5v/3.3v power supply so i did it throught 2channel shift level used 5v raspberry pi adapter to drop’s to 3.3v (i left unused data lines) because i did not now how to use other way (i’used just HV,GND with 5V and i’ve got in others 2 pin LV,GND 3.3v ) 2ch level shifter because only this way it maked me confidence of 3.3v output


@valon_hoti_gmail_com I’m sorry, I’ve mistaken your post. Anyway, you can use any good DC-DC step down to supply 3.3V. You are lucky that the 2ch level shifter is working! Normally they can’t supply enough power to supply a MCU or board.
The shown chinese breadboard power suppliers are really junk, but sometime they solve problems …

This is mostly junk, but it can supply enough power to MCU…
DC-DC 5V->3.3V


@dobova don’t worry about that since ,we here just trying to help each others with their experiences or info (in my way also lack of right words of spelling/talking language create misunderstood to others),

so in my case i’m so far behind everyone here regards electronics.

and thanx for info about dc - dc converter too.


you definetly want a power regulator, not a level shifter. I too am surprised it’s still working - they usually can only change voltages at small ampere levels, and typically a microcontroller would draw enough to exceed that. To make your own little power converter isn’t too hard. Something like an MCP1703 or even an LM1117 that has a “low drop out” meaning the incoming voltage does not need to be much higher than the output voltage before it stops regulating current is a good place to start.