Red Pill or Blue Pill?

Generic boards that are not Maple or Maple mini clones, and don't contain the additional USB reset hardware
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ahull
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Re: Red Pill or Blue Pill?

Post by ahull » Thu May 21, 2015 9:43 pm

I think I can only classify this as "semi-potted"

Image

But once I have everything ready to go into Mr Pig, I suspect there will be a little more "hot snot" applied, particularly round the USB connector and anchoring the other wires.
- Andy Hull -

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RogerClark
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Re: Red Pill or Blue Pill?

Post by RogerClark » Thu May 21, 2015 9:54 pm

Generally I find the connectors that are "through board" don't tend to be the problem.

But... Whatever works for you...... ;-)

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ahull
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Re: Red Pill or Blue Pill?

Post by ahull » Thu May 21, 2015 10:01 pm

RogerClark wrote:Generally I find the connectors that are "through board" don't tend to be the problem.

But... Whatever works for you...... ;-)
Yep... but this is going... inside a pig :shock:
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Rick Kimball
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Re: Red Pill or Blue Pill?

Post by Rick Kimball » Thu May 21, 2015 10:12 pm

ahull wrote:I think I can only classify this as "semi-potted"
I guess that is what I would expect if cut open a pig :) lot of red guts
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madias
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Re: Red Pill or Blue Pill?

Post by madias » Thu May 21, 2015 10:17 pm

Sometimes I'm glad NOT to know what you planning to do with the ST32 boards ;)
(earth closet level indicator is still the most harmless thing that comes into my head at the moment....)

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ahull
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Re: Red Pill or Blue Pill?

Post by ahull » Thu May 21, 2015 10:41 pm

madias wrote:Sometimes I'm glad NOT to know what you planning to do with the ST32 boards ;)
(earth closet level indicator is still the most harmless thing that comes into my head at the moment....)
Madias,you sound more worried than the pig.
Image
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mrburnette
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Re: Red Pill or Blue Pill?

Post by mrburnette » Thu May 21, 2015 11:21 pm

Now we just need to put an Estees rocket motor up thr pig rump and have a flying pig-o-scope.

Ray

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Rick Kimball
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Re: Red Pill or Blue Pill?

Post by Rick Kimball » Mon May 25, 2015 1:51 am

So now that I've spent more time with the "Blue Pill" I'm not sure it is a such a good choice. The voltage regulator on them is of some unknown variety and it didn't seem to last long given my messing about with the PA12 USBDP+ pin.

Each board seems to have its strengths and weaknesses. The one thing I really like about the Red / Blue pill boards is the easy access to the SWD pins. However, I can't really recommend any of those at the moment. I'm going to give one of those Baite Maple Mini's a try next.

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-rick

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Rick Kimball
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Re: Red Pill or Blue Pill?

Post by Rick Kimball » Mon May 25, 2015 5:13 pm

I resurrected my "Blue Pill" board that died. I think the problem was that the voltage regulator failed. I also did some surgery on the PA12 pin and added a resistor to see if I could get it to work properly with native USB.

This is the underside of the problematic "Blue Pill" board:
Image

I unsoldered voltage regulator?, marked (U1). I also unsoldered the 10k resistor connected to PA12 marked (R10). I have no idea why that was on PA12. Temporarily for testing, I just grabbed a through hole 1.5k resistor and just put it in place from PA12 to the 3.3v pin (see pic below). I then supplied external 3.3v power to the board from another "Red Pill" board. I had loaded up some blinky software on the blue pill so I plugged it in and pressed reset. It all worked. Feeling brave, I plugged in the USB connection on the Blue Pill. Even though it isn't supplying the 3.3v the USBD+ and USBD- pins are connected and I watched it enumerate as /dev/ttyACM2 ( I had another board plugged in and it was using ACM0 and ACM2). When I pressed reset on the blue pill board, it dropped the USB connection and then enumerated itself again.

It seems like you can use this board with the native USB if you do some minor surgery. Just now, I loaded the ASCIITable example and it sent the data output to the USB Serial port. No chance I could confuse that as I've not soldered any pins on this board yet, so all it has is native USB. Worked fine. If I press reset on the "Blue Pill" board it drops the /dev/ttyACM2 device and my putty teminal emulator window exits. I can then connect again with putty to the new /dev/ttyACM2 and it works.

Here a "Hacked Blue Pill" is being programmed and debugged from a "Red Pill" running the BMP firmware:
hack_blue_pill.jpg
hack_blue_pill.jpg (201.81 KiB) Viewed 1879 times
-rick
-rick

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RogerClark
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Re: Red Pill or Blue Pill?

Post by RogerClark » Mon May 25, 2015 10:28 pm

Rick

So.. Where does this leave things

It sounds like the actual stm32 was not damaged.

Do you think that the USB reset code damaged your regulator(s) somehow

Or do you think that in your experimentation you could have damaged the regulator etc by doing something else other than just connecting to USB and having the board re enumerate by pulling PA12 low


Just a thought, but I wonder what the smallest reliable time we can drive PA12 low

I've tried dropping it down considerably from our original test values, and I suspect it can go even lower.
Actually I tested it much lower and it was ok on my PC.

E.g. If a 1 uS pulse is enough, its less likely to do any damage. (But I know this is a somewhat hacky approach and only something that people who are willing to take the risk should entertain if there is a definite risk of damage)

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