fredag den 16. maj 2014

SimonK firmware

I heard quite a bit about the SimonK firmware and thought i would try to fiddle around with it and  try to get the firmware programmed on my Turnigy Multistar 20A ESC´s. The SimonK firmware apparently give you a smoother flight, a more responsive quad by changing the timing provided by the ESC. It also removes features that work well for planes, but are not good for multirotors, like the low voltage cut off, saving your battery. This procedure is specific to my hardware setup, not all ESC´s have the ATMEL chip, so be sure to check out this site https://docs.google.com/spreadsheet/ccc?key=0AhR02IDNb7_MdEhfVjk3MkRHVzhKdjU1YzdBQkZZRlE#gid=0 to check your configuration. All that i have done is of coarse your own responsibility if you do decide to try it, things can go wrong and you might end up buggering your ESC.

You can off Hobbykings site purchase several preprogrammed ESC´s pre flashed with the SimonK firmware like the Afro ESC series saving you the hassle of what I am doing, but I love to do it the hard way. So I purchased a USBasp programmer for 3 dollars off Ebay. 

The USB ISP programmer

The USBasp comes with a 10-pin connection cable, so i needed to create a tool to do the flashing. You can purchase a Atmel Atmega socket firmware flashing tool from Hobbyking at quite a steep price, $19, this does the job pretty quickly and does it by simply placing the tool on the MCU socket and flashing, but i prefer to save the 19 bucks, so I set out to build a tool to take care of the job.


I grabbed two, JR servo extensions leads with three wires and some header pins and a broken ESC for testing purposes.

I then broke off two rows of the header pin, keeping the plastic intact to keep the pins stable and straight.
I inserted the header pins into the JR servo leads with the long edge inserted first

 
I placed the two JR servo leads adjacently and taped them together, I was careful not to cover the wiring as I needed to follow the wire when connecting it to the asp unit


I cut the ten-pin cable and split the cable as shown above, striped the ends so I could solder the JR servo leads to the 10-pin cable.


 I found this diagram on the internet and used it to solder the cable correctly.

The Cables have to paired together and soldered, remember the correct direction as one can easily get confused and end up swapping the direction when flashing, I used a piece of tape to help me remember left from right.


Once done the cable looked like this and ready for flashing. I downloaded the flash tool and the driver for the USBasp http://lazyzero.de/en/modellbau/kkmulticopterflashtool. I installed the software and the driver, fired up the software. 

My software settings were as above.


Prior to flashing my quad ESC´s I took my broken ESC striped off the heat shrink and ran a flash test with the new cable to see if things went as planned. The USBasp provides power via the VCC cable so keep the 5volt jumper shorted on the asp


On my quad I cut out  a small section of the heat shrink, that was equivalent to the ESC that I had stripped, took off my props and simply did the same flash procedure. After flashing I simply taped the hole that I used for flashing.