stm32f103c8t6 short cuts after programming!

[HSaee.1]

Hi, I am trying to make a circuit with stm32f103c8t6 and a nrf24l0+. I attach my schematic if pcb layout needed tell me to upload that. One of the circuit work good ( the send one) the other one which is identical does not.

after soldering I did check if any short cuts happen there was not any short cut, everything was good but after I power it up and connect the stlink_v2 and programming it ( it did it just fine) I tried to work with but it act abnormal

(especially timings) after I check for vcc and gnd pin I get 124 ohm or lower impedance on them I did it with other PCBs too but same thing happens.

My regulator , regulate voltage on 3.3 volt.

st_link_v2 work I could even program this 124 ohm stm32f103c8t6.

In other PCBs impedance reduce to 20 ohm.

The files are for altium designer .

send works but revive act abnormal .

[TDK]

> In square pads sharp edge will be a problem and especially when frequency get higher and higher

Nothing in the MCU operates at such a speed where this is a concern.

Bad workmanship leads to short circuits, not square pads.

[HSaee.1]

Yes, you are right. I updated my answer after, in my last answer I explained that the round pads will help us to soldering this happen a lot to me not just in ST MCU also in Texas Instruments DSPs that one power rail left open and not soldered properly and after some small period of working with them they just show short on power rail and from my side it always solved with soldering them again and pay attention to do it right.

Based on my experience (which is not much but worked for me) in design round pads do better in accepting solder so I suggest them.

Regards:*