Fw: Syma X6 repair and mods

[Terry Fox]

Not sure if this will go through with that email address.  Trying again with a good sending email...
Terry, N4TLF


From: WB4JFI 
Sent: Sunday, June 07, 2015 4:36 PM
To: Alex Fraser ; TACOS 
Subject: Re: Syma X6 repair and mods

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.

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.

Hope that helps.
73, Terry, N4TLF


From: Alex Fraser 
Sent: Sunday, June 07, 2015 4:23 PM
To: TACOS 
Subject: Re: Syma X6 repair and mods

I tried to solder the broken traces, but just couldn't do it.  I've ordered a new main board.  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. 

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.  

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?

Alex Fraser wrote on 6/5/2015 4:08 PM: 
      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.  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.



  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.,



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 ~~~******************* Alex Fraser *******************~~~
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       No electrons were harmed in the creation of this message
         --------------------------------------------------------
 ~~~******************* Alex Fraser *******************~~~
         --------------------------------------------------------
[[[[[[~~^^^#___=>>>```/\/\**O**/\/\```<<<=___#^^^~~]]]]]]


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