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Thanks Terry, that does help. I put "SPI" and "Syma" together in
the Google box and got some hits. Sparkfun has a nice write up
<a class="moz-txt-link-freetext" href="https://learn.sparkfun.com/tutorials/serial-peripheral-interface-spi">https://learn.sparkfun.com/tutorials/serial-peripheral-interface-spi</a><br>
I also found a guy in Hong Kong who reverse engineered another quad
<a class="moz-txt-link-freetext" href="https://learn.sparkfun.com/tutorials/serial-peripheral-interface-spi">https://learn.sparkfun.com/tutorials/serial-peripheral-interface-spi</a><br>
<br>
When I looked up the <font face="Comic Sans MS">nRF24L1 RF chip it
said it had on board processing. I guess that circuitry manages
the SPI interface. </font>I'll have to go back and look at the
board again. Maybe the gyroscope chip is on the same bus too. I'll
also have to open up the transmitter again to look at that board
with my newly gained insights.<br>
<br>
<font face="Comic Sans MS">WB4JFI wrote on 6/7/2015 4:36 PM:
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<div>If you are asking what those other pins are, they are a
standard Serial Peripheral Interface (SPI) communications
interface. It is a 3/4 wire interface, usually between
central processors and peripheral devices.</div>
<div> </div>
<div>SCK is the serial clock signal, generated by the
master. MISO is the Master In Slave Out signal, used by
the slave/peripheral to communicate data back to the
MCU/master. MOSI is the opposite, Master Out Slave In,
which the MCU/master communicates data to the
slave/peripheral. There is also a Chip Enable, or Chip
Select, or a lot of other names that indicate the
Master/MCU wants to talk to that device, by holding that
pin low. Many peripherals can share the same SPI bus, and
the master only pulls down the CS or CE or CSN of the one
device it wants to talk to. There is usually only one
Chip Enable type signal per device, but your may have
more. Google SPI for more info.</div>
<div> </div>
<div>Hope that helps.</div>
<div>73, Terry, N4TLF</div>
<div> </div>
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<div style="font-color: black"><b>From:</b> <a
title="beatnic@comcast.net"
href="mailto:beatnic@comcast.net">Alex Fraser</a>
</div>
<div><b>Sent:</b> Sunday, June 07, 2015 4:23 PM</div>
<div><b>To:</b> <a title="tacos@amrad.org"
href="mailto:tacos@amrad.org">TACOS</a> </div>
<div><b>Subject:</b> Re: Syma X6 repair and mods</div>
</div>
</div>
<div> </div>
</div>
<div style="FONT-SIZE: small; TEXT-DECORATION: none;
FONT-FAMILY: "Calibri"; FONT-WEIGHT: normal;
COLOR: #000000; FONT-STYLE: normal; DISPLAY: inline"><font
face="Comic Sans MS">I tried to solder the broken
traces, but just couldn't do it. I've ordered a new
main board. </font>I almost burned my nose trying to
solder using a jewelers loup. At 10x it focused at about
an inch. I always ask doctors if they are getting rid of
any of their old optics like they use in surgery, that
stuff is expensive. I might be able to salvage this
board, I've a plan for using a ribbon cable, but for a
while this critter will sit on a shelf as I have two other
builds on the table. <br>
<br>
I did look up the chips. The RF chip was buried in a
black goo, but I found a reference to it in a RC forum.
It's a nRF24L1 which is a transceiver on 2.4 GHZ. Very
low power. In the picture it's on the RF deck. Under the
ROHS sticker is the main processor a STM8S00, 16 bit and
IIRC can communicate at 2 MHz. It has on board memory.
In the overall picture the chip to the left of the main
processor is an Invensense MPV-3050c which is the 3 axis
gyroscope. It is used in cell phones so it is fairly
cheap and available. <br>
<br>
I wonder if the labeled pins on the RF deck are
recognizable to some folks right off. Vdd and GND I got.
MISO, MOSI, SCK, CSN and CE even looking at the data
sheet were strange to me. Are these common to all
processors?<br>
<br>
Alex Fraser wrote on 6/5/2015 4:08 PM:
<blockquote type="cite"><font face="Comic Sans MS"> I
have to replace two motor assemblies on my Syma X6
quad copter. That is a simple straight forward solder
job. I thought while I had the board off the frame I
might modify the antenna for more range. In the first
picture you can see the layout. The board is 1.82"
square</font>. There was a small board I call the "RF
deck" which laid flat on the main board. I suppose that
is so they can put whatever radio they want on the main
board. I pulled the RF deck upright to trace the ground
so I could find a pad to solder on the coax shield for
the antenna, They had attached the RF deck to the main
board in the board construction, in an oven I guess, so
three connections on the bottom were soldered to traces
under the board. The traces of course broke when I
pulled on the board. When I fix it I'll leave it
upright and just hope it don't cause an RF problem, pick
up noise or vibration etc.<br>
<br>
<br>
<br>
I circled the injured traces. It is at 2.4 GHz. I have
no idea what "RHOS" is but the label peeled off and I'm
going to search for that chip just for fun.,<br>
<br>
<br>
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</font>
<pre class="moz-signature" cols="72">--
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No electrons were harmed in the creation of this message
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~~~******************* Alex Fraser *******************~~~
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