Kisssys Expansion Board
The Kisssys expansion is a small, simple and versatile expansion board for the M4. It has the following functions:
- 4 PWM lines for ESC´s or servos
- uSD card reader
- UART1 port for telemetry, powered from stepup
- Option to mount Polulu stepup converter, fuse protected
Refer to the PDF assembly sheet for details on component placements.
Make sure to line up the 10 pin 0.05″ headers correctly with the M4 board its beeing assembled for.
The board is designed to take a Polulu step up converter module to allow powering 5V (or 3.3V) peripherals from a 1S lipo. This can be handy for using telemetry modules, FPV gear or receivers that need 5V on 1S based crafts.
The module sources power from Vcom+, which is the switched 1S battery supply from M4. It is protected with a 500 mA resetable fuse. (F1)
The module outputs its voltage to the “O” pin on the expansion. This pin then feeds the power pin on the UART connector. If you have a beta board (V1), this is the only way to power the UART port to run a Bluetooth module or other telemetry module.
Supplying 3.3V onto the UART port without using a stepup
This method can only be used on the release (V2) boards. It allows to use the internal 3.3V Buck/boost converter on the V2 boards to power the UART port with 3.3V for something small like a BT module.
!!!You can ONLY do this on a V2 board!!
Solder a small wire from C3 over to the “O” pin like this:
The JST-SH connector provides the UART1 connection from the M4. This is set up for Mavlink telemetry, so all you need to get wireless telemetry on M4 is to connect a 3.3V wireless serial interface.
A popular option is the HC-0x based modules, like this one:
For really small builds, you can remove the module from the backplane (or buy one without a backplane) to get a very small and light telemetry option.
You can just solder a JST-SH cable to the board itself like this:
Remember to rearrange the JST-SH connector pins to match:
Motor connections M5 thru M8 is broken out to two 0.1″ pitch headers. Note that there is ONLY the 4 PWM lines and 2 DGND connections available, so if connecting a servo to M5 thru M8, you need to powersupply it from another source.