I2C to PWM Converter “AfroI2C Tokyo Drift”
Hardware and Connection
NOTE The converter ships pre-conﬁgured to be powered by 5V from 1st ESC
Battery +5Battery -I2C connector
152Firmware update

ESC Power
4Power LED
98

External 5V
Status LED

PWM Output 1-87Fig. 1

3Conﬁg Jumper

6Ground

1. I2C connector. GND, SCL (C), SDA (D) pins from left to right. Connect these to C, D and Ground pads
on Flight Control. For convenience, standard servo cable can be used. Black = Ground; Red = C; White = D.
2. Firmware update connector. TTL serial at 5V levels. GND, TX, RX pins from left to right. Can be connected
to any TTL serial/USB converter. Serial parameters are 115200 baud, 8 bit, no parity, 1 stop bit.
On power-up, startup message is output through this connector. Serial console can be used for advanced
converter settings to adjust PWM timing and various other parameters. See “Advanced Conﬁguration”.
3. Motor conﬁguration jumper. All pads untouched (default) = Quad1-2 bridged = Octo
2-3 Bridged = Hexa
1-2-3 bridged = Tri
4. ESC Power jumper. When shorted, use 5V from ﬁrst ESC. This is default conﬁguration.
Do NOT connect battery power ( 5 ) with this jumper in place.
5. Battery +/- terminals. Do NOT use if powering by 1st ESC or external 5V.
6. External 5V connector. Any other 5V power source. Can be taken from Flight Control, etc.
7. Ground connector. Used when external 5V power is used. Otherwise leave unconnected.
8. PWM output to ESC, standard pinout. Only the Signal pins are needed for operation if external poweris used. At least one ground pad must be connected, either ( 7 ) or any of the PWM grounds.
Top = Signal
Center = 5V (only 1st connected)
Bottom = Ground
9. Status LED

I2C to PWM Converter “AfroI2C Tokyo Drift”
Conﬁguration and Usage
Automatic ESC Calibration (Bind-Plug)
1. Disconnect I2C plug from the board (Fig.1 1 )2. Connect Bind-plug from your receiver (or short out pins D and GND)
3. Apply power to all ESCs and I2C converter.
4. Status LED (Fig.1 9 ) will blink, while controllers will make calibration beep sounds.
5. After status LED ﬁnish blinking and stays on, remove power and Bind-plug andre-connect I2C connector.
6. Each ESC must still be individually programmed to Medium or High motor timing and low
cut-off voltage - bind plug calibration ONLY sets the throttle range.

WARNING Remove propellers or tie down the model before attempting ESC calibration.
Minimum throttle setting for Mikrokopter
In order to avoid full motor stop when using converter with MK-FC,
MinGas setting needs to be adjusted to a higher value. On main screenof MKTools, go to the “Motor test” tab, check the “Active” box, andselect “ALL” for the address. With props removed, slowly increase thethrottle slider until all motors start. If all motors don’t start at same time, repeat the bindplug
calibration. Note the value (12 in this example) that the motors started at. Now exit Motor
test and go to Settings, Misc tab. Replace the default Min Gas valueof 8 with the number from Motor test + 2. So in this example,
Min Gas would be set to 14.

Standard operation and Status LED
On power-up the Status LED (Fig.1 9 ) blinks rapidly for a few seconds, then blink more
slowly to count the number of conﬁgured motors. If motor data is received from FC,
Status LED will remain off. If I2C connection is interrupted (cable removed for example),motors will be put to emergency throttle setting (default 0) and Status LED will light.
1. Connect Standard ESC to PWM Output pins 1-8 (Fig.1 8 )Motor #1 is left-most connector.
2. Calibrate and program ESC (Only needs to be done once)
3. Perform Min Gas setting for Mikrokopter (Only needs to be done once)
4. Fly around.
Manual Revision 2011.06.27

I2C to PWM Converter “AfroI2C Tokyo Drift”
Advanced Conﬁguration
Firmware update using MK-USB
1. Using a servo cable or similar, connect
converter to MK-USB as shown in Fig.2.
2. See readme.txt included with AfroFlashpackage for complete command-line
Fig. 2instructions.
3. After typing in the update command,
without pressing <Enter>, power up the board and press <Enter> key while the Status LED(Fig.1 9 ) is ﬂashing.
4. After update is complete, disconnect power and MK-USB.
5. For more detailed instructions, see readme.txt included with AfroFlash package.

Using Serial Console
Connect a USB-Serial converter such as MKUSB the same way as described for Firmware
update. Obtain a serial terminal program, such as PuTTY or TeraTerm Pro or HyperTerminal.
In Fig.3, PuTTY is used as example. USB-Serial port is COM4, andspeed needs to be set to 115200. In Fig.4 below shows a sample
serial console session. On power-up of converter, welcome message(1) is displayed. Pressing “?” and <Enter> key will show brief help
message (2) and (3). Entering “i” displays current conﬁguration (4).
Fig. 3Things to note here is PWM period - 400Hz, pulse start/end times 1000us to 2000us, number of conﬁgured motors - 4, and emergency throttle value.
Emergency throttle is activated after ~100ms of no I2C data and will set all motors to thisthrottle value to allow more controlled descent. Obviously this should not be set above hover
point. For commands that take parameters, enter command, space, and number. Backspace
key does not work, so be careful entering numbers. For example to set PWM period to 250Hz,enter “p 250”. If everything is OK, converter will print out the new settings. Once conﬁguration
is done, use the “w” command to write settings to EEPROM (5).

WARNING Do not change

PWM period, pulse start/end or
emergency throttle with propellers
connected or if you don’t know what
you’re doing. Setting pulse start/end
is realtime, and will take effectimmediately on pressing Enter key.
Incorrect setting can cause all motors
to run at full throttle, etc.

Fig. 4