Silicon Labs USB Toolstick Mod for BLHeli Flashing

May 14, 2012

This is part 1 of my series on the Blade mSR X Brushless Conversion using Steffen’s BLHeli firmware for the XP 3A ESC. The information in this post is also applicable for those of you doing a brushless conversion on the Blade mCP X and will be flashing the XP 7A and XP 12A ESC. All those ESC, along with the DP 3A and Supermicro 3.5A uses a Silicon Labs based chip, so you will need to do the following modification.

Step 1: Obtain the SiLabs USB Toolstick:

The USB Toolstick can be purchased from Digi-Key or from Silicon Labs themselves. Digi-Key ships it out fast and there was no order minimum.

Step 2: Open the USB Toolstick:

Using a guitar pick or a folded over piece of plastic from toys/food packaging, you can insert between the halves like so and twist to pop the halves apart. Then work around the perimeter to easily open the plastic case to get into PCB board. This prevents any damage to the plastic housing which we will reuse later to reassemble the USB Toolstick.

Wedge a piece of plastic to open up the USB Toolstick

Step 3: Soldering Points – Wiring:

Here’s the solder points you need to be aware of. We will use red, black and white wires to match Steffen’s original post.

Side A: Here is where to solder the white (C2Data) wire. It also shows the two pins (2 and 4) that will need to be soldered together. (Alternatively, if you need to be able to use the USB Toolstick for other projects, you can simply wire up a switch that when enabled, bridges those two pins.)

The white wire solder point and the two pins you need to solder together.

Side B: On the reverse side, you can solder a red (C2CLOCK) and black (GND) wires to these two legs.

Solder the red and black wires to these pins.

I run the red and black wires through the holes so all three wires are on one side like so.

SiLabs USB ToolStick all wired up.

Step 4: Drill holes for the connector:

I wanted to add a connector. So I drilled 3 holes into the USB ToolStick’s case. This was easily accomplish by temporarily taping the connector I am using to the case to act as a template. Then used a 1mm drill bit to drill at each point of the connector legs. Simply insert the connector through the Toolstick housing and soldered up the red, black and white wires to it. The connector should be held in tightly if done right. The connector I used came with my XP 3A ESC.

Alternatively, you can simply drill a single hole to pass all three wires through the case. Then solder up a connector to them outside the case.

Here is a photo of the result of this step. I can see the position for the black, red and white wires to help me orient the mating plug that goes to the ESC.

USB ToolStick with connector

Step 5 Final: Reassemble USB ToolStick Case:

Once the wiring is done, it’s easy to snap back on the case you took apart in step 1. Here is a look at the modified USB ToolStick with the connector installed into the case. We are ready to use the modified SiLabs USB Toolstick to flash the ESC with BLHeli firmware. This will be outlined in Part 2 of the mSR X Brushless Conversion series.