Open SW102 by cutting a side part and solder SWD wires
To open SW102, cut a side part as seen on the following pictures. Please be careful when removing this side part as in the end you will put it back and glue it, so, avoid any damage to this part.
Use a hand saw for metal and to cut the side part:
Break the side part break, you can pull it with pliers. Here are exposed the pads of SWD pins. I had to I pull with pliers a small rubber sheet and had to cut a bit of the plastic with a cuter knife so I could have a better access to the pads using a fine tip of a soldering iron:
Finally I soldered carefully the 3 wires for STLinkV2 and made sure there was no short circuits on them before power up the SW102 from the battery.
Solder the wires from the STLinkV2 as follows:
| SW102 | ST-LINK |
|---|---|
| GND | GND (pad number 4, when start counting from left side on the bellow picture, black wire) |
| CLK | SWCLK (pad number 3, when start counting from left side on the bellow picture, white wire) |
| DIO | SWDIO (pad number 2, when start counting from left side on the bellow picture, gray wire) |
| 3V3 | 3.3V (Optional, no need to wire if you are power up the SW102 from the battery. Pad number 1, when start counting from left side on the bellow picture, not connected on the picture) |
Note that I am not using the 3V3 as I am powering the SW102 from battery -- I think this is better as it is one less wire to solder.
After flashing the bootloader and the firmware, it runs!! Now you can remove the SWD wires as you should never need them again:
Finally you can use the side part previously removed and glue it with black silicone (you can probably buy it on a local shop). After all this, the key pad is working perfectly as original:
