preenfm Forum
PreenFM => preenfm2 and preenfm3 => Topic started by: kreeper_6 on May 03, 2019, 07:35:00 AM
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I ran a DRC on the F405 brd file in eagle and it is showing Pin 64 and C1 not connected to VCC, is this a bug? Connecting PC13 through a via on the bottom layer would reconnect the VCC floater.
(https://i.imgur.com/l7rj3AT.jpg)
(https://i.imgur.com/TeIYN9P.jpg)
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Its related to your Eagle settings. Distances etc measurements. Make the numbers smaller and re.check.
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As far as I know, these distances are in the published brd file. I've seen that floater on various PreenF405 boards, there is nowhere for it to connect.
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Yes seems like VCC does not reach pin 64 of the MCU.
The 3 other VCC pins are enough to power correctly the stm32F4 as it's very stable in a preenfm2 usage.
Eagle 6.5.0 that i used for this PCB does not complain when runing DRC .
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I noticed this as well. I added a jumper from pin 64 to 3.3v on the module. Don't assume that the 3.3v and GND pins on a semiconductor device are connected together inside the chip - in some devices they are not and you could be powering a section of the part through some parasitic internal path. Not good.