Hi all!
Today the PCBs have arrived and I spent some tiem building the first prototype. Soldering after a long time was quite fun but worked great.
However, I got stuck for way too long due to two pin-out problems: * the voltage regulator pinout is completely mixed up * the reset switch pinout is wrong and causes the device to be in nRESET all the time
I've now applied some re-work and the CPU seems running. However, due to some unknown (probably USB pull-up related) problem, I cannot see it enumerate on USB yet.
Will keep you posted about my further progress.
I've created tickets for the bugs in our trac (http://bb.osmocom.org/trac/query)
Regards, Harald
Hi Kevin!
Can you please let me know how you entered/imported the BC847 library/module for kicad? Is it something you did yourself or imported from some public reference library?
The reason why I'm asking: It should be a very common component and part of a standard library. However, the pinout is wrong. Specifically, pins 1 and 2 seem to be mixed up (base and emitter switched).
This could be a) a result from broken public library (somebody should have found this before) b) something we entered wrongly into the simtrace library (happens...) c) something wrong about the mirroring of the part, e.g. because we call the soldering side 'front/top side' in our design. Normally in SMD, as far as i understand, everything happens on the solder/back side.
Regards, Harald
Hi,
On 14.06.2011 23:18, Harald Welte wrote:
Hi Kevin!
Can you please let me know how you entered/imported the BC847 library/module for kicad? Is it something you did yourself or imported from some public reference library?
error : pin 1 and 2 of BC847 are swapped source : KiCAD way of doing footprint + wrong verification on my side (must have used another NPN transistor or BC847 datasheet to check) effect : the two BC847 NPN transistors are affected. the current flow in the wrong direction workaround : solder the BC847 upside down
in Kicad there is no footprint for BC847. the footprints are general. I assigned the SOT23 footprint for BC847, but the footprint is only about the pad size and position. It does not ensure the correct pin assignment. I verified them wrong.
Kevin
Hi,
On 14.06.2011 22:23, Harald Welte wrote:
Today the PCBs have arrived and I spent some tiem building the first prototype. Soldering after a long time was quite fun but worked great.
good news
However, I got stuck for way too long due to two pin-out problems:
bad news
- the voltage regulator pinout is completely mixed up
see next mail
- the reset switch pinout is wrong and causes the device to be in nRESET all the time
error : the pin numbers are wrong source : it's my bad, I draw the footprint and read/remembered the circuit diagram wrong. effect : the two switches are affected. the endpoint are constantly connected (instead of "switched") workaround : turn the switch by 90° (CW/CCW), then solder
kevin
-
Harald Welte -
Kevin Redon