microRusEFI Wiring

Connector Pinout

Interactive Pinout

WARNING: for historical reasons microRusEFI pin numbers do not match Molex numbers on the plastic


microRusEFI photo

Rear side of PCB

microRusEFI image


In some cases without "main relay output +12v" both pins #1 and #5 should be connected to the single source of +12v.

Pin #1 feeds ETB H-bridge, battery voltage sense, gp5 & gp6 high-side +12v, TLE8888 H-bridges.

Pin Types

These tables provide technical information about the different types of pin found on microRusEFI.


ID Type Notes & Limits
12V Power supply 9-22V operating, 5A fuse recommended
pgnd Power ground Solidly ground directly to chassis or engine block.
sgnd Signal ground Sensor ground. Do not ground to engine!
5v 5V sensor supply 5V supply for external sensors. 200mA maximum per pin.


Pin Name Notes & Limits
#33 GP3 Stepper Coil #2
#34 GP2 Stepper Coil #1
#35 GP1 Stepper Coil #1
#43 GP4 Stepper Coil #2


ID Type Notes & Limits Possible functions
at Analog temperature Analog temperature (thermistor) input. 2.7k/TBD pullup resistor to 5v Thermistor temperature sensor, fuel level sender (variable resistor type)
av Analog voltage Analog voltage input. 500k pull down to GND Analog voltage sensor (MAP, TPS, acc pedal, oil pressure, etc)
vr Variable reluctor VR crank input VR sensors including crank, cam, vehicle speed
hall Hall cam/crank TBD pull up to 5v hall sensor for cam/crank Hall sensors including crank, cam, vehicle speed


ID Type Notes & Limits Possible functions
inj Injector output Low side, 2.2A maximum
Only saturated (high impedance) injectors are supported.
Injector, general purpose low side
ign Ignition output 5V push-pull, 250mA maximum Ignition coil, general purpose 5V push-pull
ls High power low side General purpose low side output, 4.5A maximum General purpose low side, injector
gp_high General purpose high side General purpose high side push output, 5V/12V (internally selectable based on JP2 jumper) 250mA maximum General purpose 5V/12V high side, ignition coil
gp_low General purpose low side General purpose low side pull output, 12V 500mA maximum General purpose low side
gp_pp General purpose Push-Pull General purpose push-pull (low and high side) output, 600mA Bipolar IDLE stepper, relays, solenoids
mr Main relay Dedicated main relay output. Low side turned on with power, 800mA maximum. Main relay
etb Electronic throttle Dedicated electronic throttle outputs. Connect a brushed motor
throttle body directly to these two pins.


ID Type Notes & Limits
usb USB USB tuning interface
can CAN bus CAN communication

USB cable green wire: USB D+ DATA+

USB cable white wire: USB D- DATA-

USB cable black wire: ground

HOWTO wire external USB

USB cable red wire: +5v (would not work via microRusEFI connector for versions < 0.5.0)

Hall type Crank sensor

See TLE8888 datasheet figure 71 R9=DNP R15=DNP R17=2.7K pull-up to 5v

R12=10K R13=0R

front hall front lower

Extra pins

microRusEFI exposes the following pins in addition to the primary 48 pin connector:


x | N | Name | Possible functions (not all listed!) | |----|-------------| ---- | | 9 | GNS | GND | 4 | VDD | 3.3V | 1 | 5V | 5V | 2 | 12V | 12V from Main Relay | 3 | PB8 | I2C1_SCL or CAN1_RX | 6 | PB9 | I2C1_SDA or CAN1_TX | 8 | PC10 | SPI3_SCK or USART3_TX or UART4_TX | 5 | PC11 | SPI3_MISO or USART3_RX or UART4_RX | 10 | PC12 | SPI3_MOSI or USART3_CK or UART5_TX | 7 | PA15 | SPI3_NSS (Chip Select)

J2 Interactive Pinout

Three GPIOs are available on J2 (SWD) connector. If you are not going to use debuger J2 connector can be used for other purposes. | N | Name | Possible functions (not all listed!) | |----|-------------| ---- | | 7, 8 | GND | GND | | 1, 2 | 5V | 5V | | 3, 4 | VDD | 3.3V | | 5 | SCK | SWD clock or PA14 gpio (no alternative functions) | | 9 | SWDIO | SWD data or PA13 gpio (no alternative functions) | | 6 | SWO | SWD/JTAG data out (?) or SPI1_SCK or SPI3_SCK | | 10 | NRST | CPU reset input (active low) |

For HW version 0.5.0 and newer some additional GPIOs are available on testpoints around STM32.


Testpoint Interactive Pinout

Tespoint GPIO Possible functions (not all listed!)
J9 PC13 GPIO only
J10 PE6 TIM9_CH2
J11 PE5 TIM9_CH1

Please refer to STM32F407 chip documentation for full list of alternative functions of GPIOs listed above.