gEDA-user: powermeter project update

[DJ Delorie <dj@xxxxxxxxxxx>]

In case folks are curious of the status of this project...

Power supply is still broken.  It provides basically 5v, but cannot
maintain regulation under load.  I ordered a replacement chip and an
eval board so I can compare mine to theirs.  Meanwhile, I'm running
off USB power instead.  The AC power is still plugged in as the ADE
chips need the reference to calculate real vs imaginary power.

USB circuit worked fine despite being a QFN32, but I misused one of
the CBUS pins.  The FT232R has five CBUS pins, but only four of them
can be used as GPIO (The fifth can be configured for any of the other
options, like LED control or sleep status).  Silly me, I wired the
fifth for a GPIO purpose.  It's really hard to solder a wire onto a
QFN pad, but I managed.  I might do a new footprint for that part with
copper pads that stick out more, just in case.

The R8C chip worked just fine after I manually resoldered all the
pins.  My attempts at making a cheap paste mask, or my choice of paste
(syringe vs tub), resulted in very inconsistent paste application.

The ethernet circuit pretty much just worked, despite being a QFN28.
The chip gets pretty warm, I'll have to be careful to make sure the
thermal pad is properly soldered on future boards.  Hopefully I'll get
newer steppings in my next order; the older chips have a minimum SPI
speed of 8MHz to ensure reliability but the R8C can only do 5MHz.  The
latest stepping no longer has that minimum limit.  It seems to work OK
for me anyway, I can ping it from my PC.

The ADE chips just worked, both of them (I only populated two out of
16 on this test board), even the zero crossing interrupt.  However, I
managed to swap SDI and SDO in the design, so more rework before the
next boards.

Software-wise, I've decided to go with uIP.  The R8C has data flash
for storing mac/ip info and calibration data, and uIP is significantly
smaller than lwIP (I only have 3k of RAM).  I got an ENC28J60 driver
for uIP from the avrfreaks archive, modded it to work with the R8C spi
hardware.  All it needs to do is spit out UDP packets once in a while
with power usage information.

Anyway, that's where it is.


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