Ports and Pins by Function

This page gives an overview and description of the many connections on the STorM32 main boards. For the details of their function and usage please consult the other wiki pages.

The info on this page refers to the v1.3, v3.3 and v4.1 STorM32 boards. The pins on the v1.31 board are identical to that of the v1.3 board. The location of the ports are described in Pins and Connectors.

Except of the ports POT, BUT and UART2/ESP, all ports are 5 V tolerant, which means that you can apply signals with voltages of up to 5 V to their pins without damaging the board. The ports POT, BUT and UART2/ESP are however not 5 V tolerant. The voltage on the POT, BUT and UART2/ESP pins must not exceed 3.3 V.

The 3.3 V pins must only be used as supply. Never apply any voltage to a 3.3 V pin (unless you're an expert and know what you do).

Comment: The pin assignments below refer to the pin assignments on the STorM32 main boards; for NT modules they can be different, such as for the NT and NT-X bus ports.

MOT0, MOT1, MOT2

Function: These ports are the connectors for the motors (MOT0 = Pitch, MOT1 = Roll, MOT2 = Yaw by default).

NT Bus Port

Pins: Gnd, Rx, Tx, 5V

Function: Connector for the NT bus, where all NT modules go to. The Rx and Tx lines are 3.3 V only. The power line which is sourcing the NT modules is nominally 5 V.

Comment: The sequence of the Rx, Tx pins is swapped as compared to the NT bus port on the NT modules!

NT-X Bus Port

Pins: Gnd, Rx, Tx, 5V, Gnd, BAT, BAT

Function: Connector for the NT bus, where all NT modules go to, inclusive a pass through for the battery voltage. The Rx and Tx lines are 3.3 V only. The power line which is sourcing the NT modules is nominally 5 V. The battery lines source the NT motor modules.

Comment: The sequence of the Rx, Tx pins is swapped as compared to the NT bus port on the NT modules!

Comment: The NT-X port is often populated with a 6-pin connector instead of a 7-pin connector. If so, then the 2nd BAT pin is not present.

WARNING: Be very careful with that port, the BAT pins carry the battery voltage and any contact to any of the other pins will immediately destroy the STorM32 board.

RC

Pins: Gnd, RC-0, RC-1, RC-2

Function: The pins on this port can serve multiple functions, depending on parameter settings.

Their default function is to provide inputs for RC PWM signals. Typically RC receivers are connected to here. The input pulse lengths of 1 ms to 2 ms are converted to the value range -500 ... 500. The frequency of the input pulses can vary, and can be as high as 430 Hz.

The pins can also assume alternative, different functions:

• Pin RC-0: Can be configured as input to read the signal from a Spektrum satellite, or Futaba S-bus and other serial protocols, or as UARTX serial (UARTX-Rx).
• Pin RC-1: Can be configured as output to generate PWM servo signals or as UARTX serial (UARTX-Tx)
• Pin RC-2: Can be configured as input for sum PPM signals.

RC2

Pins: Gnd, RC2-0, RC2-1, RC2-2, RC2-3

Function: Inputs for RC PWM signals. Typically RC receivers are connected to here. The input pulse lengths of 1 ms to 2 ms are converted to the value range -500 ... 500. The frequency of the input pulses can vary, and can be as high as 430 Hz.

POT

Pins: Gnd, POT-0, POT-1, POT-2, 3.3V

Function: These three pins are connected to the analog digital converter (ADC) of the microprocessor and hence can digest analog signals. The analog signal is converted to the value range -500...500. Typically the central pins of potentiometers of e.g. a joystick are connected to here; the hot and cold potentiometer pins go then to the Gnd and 3.3V pins.

WARNING: Never apply signals with voltages larger than 3.3 V to any of these pins, this will destroy your board immediately!

BUT

Pins: Gnd, BUT

Function: This pin is actually also connected to the analog digital converter (ADC) of the microprocessor, but the analog signal are processed differently than those on the POT port. Currently this port is used to connect a key or switch to it.

WARNING: Never apply signals with voltages larger than 3.3 V to any of these pins, this will destroy your board immediately!

AUX

Pins: Gnd, AUX-0, AUX-1, AUX-2

Function: These are general purpose pins. Currently they are used to connect up to three keys and/or switches.

UART

Pins: Gnd, Rx, Tx

Function: Standard serial port to communicate with the board. The serial is set to 115200 bps by default, no parity bit, one stop bit. Details of the communication protocol can be found in the article Serial Communication.

UART2 / ESP

Pins: Gnd, Rx2, Tx2, RST, GPIO0, 5 V

Function: Second serial port to communicate with the board. Typical use is as interface to communicate with a camera, see NT Camera.

WARNING: Never apply signals with voltages larger than 3.3 V to any of these pins, this will destroy your board immediately!

I2C (NT Bus Port)

Pins: Gnd, Tx, Rx, 3.3V

Function: Connector for the NT bus, where all NT modules go to.

Comment: In I2C-based setups, the pins of this port are assigned to the I2C lines Gnd, SCL, SDA, and 3.3V. Hence the name "I2C" of this port.

I2C#2

Pins: Gnd, SCL, SDA, 3.3V

Function: Connector for an external I2C-based 2nd MPU module, if this is to be used instead of the on-board MPU.

SPK

Pins: 3.3 V, Gnd, Signal

Function: Connector for a Spektrum satellite receiver.

IR

Pins: Gnd, IR

Function: Allows to connect an IR led to remote control a camera.

SWD

Pins: SWDIO, Gnd, SWCLK, 3.3V

Function: Connector for programming the microcontroller using a ST-Link/V2 programming tool.

Comment: The SWD port is located right above the AUX port on the board.