EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: krapht on January 21, 2016, 07:21:45 pm
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So my board finally came back from China. Decided to get it assembled because I am not at all comfortable with QFN and 0402 by hand, which were a necessity in this design for decoupling reasons.
Next step: gingerly power it on and hope I can at least talk to it over JTAG without magic smoke leaking out.
(http://i.imgur.com/KrQGo9o.jpg)
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Let us know how it turns out. Thats a nice looking board, nice job on the layout.
What company did the assembly? Cost effective? What were they like to deal with?
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So as it turns out the FTDI chip on the board takes forever to power on and settle. The bootloader on the MCU I'm using goes into a set of different modes based on the voltage on certain GPIO pins, GPIO pins which are glitching on power-up since they are also connected to this FTDI chip which is actually driving them with hard logic 1/0s, overpowering my pulldown resistors.
I can fix this, but I have to cut the traces and write a program to flash the chip memory via JTAG, which is a little involved since the flash isn't memory mapped...
I used an American company called Advanced Assembly. I don't actually know if they outsource to China, but I have a feeling they do since the manufacturing engineer I spoke with was Chinese and was writing me emails pretty late in the day. I forgot exactly how much I paid but it was around $600 for 1 piece, 6 day turn, turnkey, their standard 4-layer PCB stackup which is 1mm core and 2x2116 ply each side.