STM32 correct orientation?

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nevetsokyeron
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STM32 correct orientation?

Post by nevetsokyeron » Sun Aug 28, 2016 4:16 pm

I'd like to confirm I'm placing this STM32 chip in the correct orientation on an MI Warps I'm building.

The Warps pcb has a dot in the upper right corner of the pin layout. The chip (shown below) has a dot in either corner so I am confused.

Is this chip shown in the correct orientation? (Bigger dot in upper right?)

Thanks!

Image

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lasesentaysiete
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Post by lasesentaysiete » Sun Aug 28, 2016 4:28 pm

small dot on the chip is the one that counts. So on the warps pcb, the MCU is "upside down". Just like on Elements

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Post by nevetsokyeron » Sun Aug 28, 2016 4:54 pm

lasesentaysiete wrote:small dot on the chip is the one that counts. So on the warps pcb, the MCU is "upside down". Just like on Elements
AHA! Thanks so much!

This would explain my inability to program it!

I was having problems with a short somewhere so I ended up pulling it off the board - good thing as it was previously upside down.

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Post by guest » Sun Aug 28, 2016 6:23 pm

if you powered it up while backwards, there is a good chance the chip is fried. a handy trick for figuring out orientation on confusing ICs like that, is to see if there are multiple ground pins (hopefully not in symmetric locations), and measure for a short with your multimeter. in the case of the STM32 chips, the datasheet is of no help in identifying the pin1 marker, as the drawing only shows a single dot.
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Post by nevetsokyeron » Sun Aug 28, 2016 8:34 pm

guest wrote:if you powered it up while backwards, there is a good chance the chip is fried. a handy trick for figuring out orientation on confusing ICs like that, is to see if there are multiple ground pins (hopefully not in symmetric locations), and measure for a short with your multimeter. in the case of the STM32 chips, the datasheet is of no help in identifying the pin1 marker, as the drawing only shows a single dot.
Yeah - I had a pretty hard time testing with my meter and looking at the data sheet. Figured I should just ask the Muffs to confirm or deny.

I had two of these that I removed from the Warps boards I was working on. Not sure which one I put back on the fully populated one - But... the Warps took the flash and appears to be working.

Any idea how to test the chip to see if it's fried without re-mounting it on the other board?

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Post by guest » Sun Aug 28, 2016 9:45 pm

i dont think there is a good way to test the chip without putting in a circuit. but, you dont neccesarily need to solder it. ive had luck precisely aligning an IC, and then just pushing down on it while i hit the "program" button on the computer. sometimes it works. you can give it a try, and if it fails, then solder it down to just make sure.
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Post by nevetsokyeron » Sun Aug 28, 2016 10:07 pm

guest wrote:i dont think there is a good way to test the chip without putting in a circuit. but, you dont neccesarily need to solder it. ive had luck precisely aligning an IC, and then just pushing down on it while i hit the "program" button on the computer. sometimes it works. you can give it a try, and if it fails, then solder it down to just make sure.
I think on the warps it needs to have the power (3.3v) stuff there to supply the chip or it won't program. After taking that chip on an off a couple times now, my soldering skills are improving so I might as well mount it up and see what happens.

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Post by valgamaa » Mon Aug 29, 2016 12:05 pm

The ST datasheet has a diagram showing the pin 1 and includes the chip text in the picture to remove all ambiguity. The pin 1 ident is the one that is top right when the text is upside down.

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