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A project log for My project site activities

This is a quick summary of my new site and what I am doing.

K.C. LeeK.C. Lee 08/16/2018 at 22:210 Comments

Cheap Xilinx Virtual Cable Alternative?

Made a JTAG dongle using ESP8266 module.  Based on https://github.com/gtortone/esp-xvcd, but I made some changes to GPIO pins and added proper level translation.

Haven't started with the firmware.  At some point I'll be removed the Arduino digitalwrite() junk as the abstraction are badly and sloooooooow for bitbanging.  

Sneak peek at the 1 sq. inch layout if and when I am happy with the design.

The $20 FPGA board has arrived (18th Aug) from China.  It took a bit of damage with the JTAG pin sticking out and slightly bent.  Canada Post put the package in a a big Canada Post plastic bag.

The PCB side by side with a "credit card".

portable f103

PCB arrived from OSH Park a couple of days ago.

Aside from the stereo connector a bit longer pushing into a couple of parts and a bunch of soldering mishaps,  things are looking okay.  I am in the middle of writing driver code.

Smart bench supply

A couple of modules and some plastic knobs showed up in the last couple of days.

The C$ 2.58 buck-boost one has a possibly XL6019 (180kHz) relabelled as XL6009 (400kHz).  I saw 180kHz switching waveforms on my scope.

Compare the texture of the one on the left vs the one on the right hand side (fake).  The fake one has some fine scan lines vs the textured surface on the left

There are a couple of possibly fake or obsoleted ELNA labelled cap.  The ripple (lol 200mV) does not match their claim of 30mV even at low load.  They do have decent inductors.

The C$ 1.78 XL6015 (180kHz) buck module is probably using real part as I see 188kHz on my scope and the ripple is actually decent.  The inductor is getting warm - they probably use the wrong type of core that is too lossy.  Might move inductor from the buck boost module here.

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