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OpenBCI 32bit Library

The official library for the OpenBCI 32bit Board.

Table of Contents:

  1. Minimums
  2. Installing
  3. Upgrading
  4. Downgrading
  5. General Overview
  6. Includes
  7. setup()
  8. loop()
  9. System Overview
  10. Reference Guide
  11. Functions
  12. Enums


You just opened your OpenBCI (congrats!) and want to get started programming the firmware right now?! Ok, ok do the following minimums!

  1. Install the dongle drivers from FTDI for your operating system.
  2. Download the latest Arduino IDE software from the Arduino site
  3. Follow the 2nd installation method "Manual install by copying ZIP file" to install the latest chipKIT-core hardware files from the chipKIT-core wiki


  1. Download this repository zip or clone this repo (we clone directly into the libraries folder for development)
  2. Download OpenBCI_32bit_SD
  3. Move both of the folders into your libraries folder (please make a folder in Arduino named libraries if you don't have one)
  • Mac OSX: User/Documents/Arduino/libraries
  • Windows: /My Documents/Arduino/libraries
  1. Restart Arduino IDE
  2. Open DefaultBoard.ino for a full featured example.
  3. Hack and make awesome stuff!


Checkout the upgrade guide!


Have a bunch of custom firmware based on the original firmware? Have no fear for previous releases are here and here for the radios if needed.

General Overview:

Your needs dictate what you need to include! This saves a ton of precious memory space!


Default OpenBCI with SD Card Functionality

In order to use the SD card write functionality, you must not only include the file SD_Card_Stuff.ino located in examples/DefaultBoard, you must include the following:


#include <OBCI32_SD.h>
#include <DSPI.h>
#include <EEPROM.h>
#include <OpenBCI_32bit_Library.h>
#include <OpenBCI_32bit_Library_Definitions.h>

Variables used by SD_Card_Stuff.ino:

boolean addAccelToSD = false;
boolean addAuxToSD = false;
boolean SDfileOpen = false;

Bare OpenBCI Board with no SD card


#include <DSPI.h>
#include <OpenBCI_32bit_Library.h>
#include <OpenBCI_32bit_Library_Definitions.h>

You do not need to declare any variables...


Accel (default)

void setup() {
  board.begin(); // Bring up the OpenBCI Board
  // The board will use accel data by default


void setup() {
  board.begin(); // Bring up the OpenBCI Board
  board.useAccel(false); // Notify the board we want to use aux data, this effects `::sendChannelData()`


We will start with the basics here, and work our way up... The loop function can be thought of as the meat and core executor of the OpenBCI_32bit_Library functionality. Keep in mind the main purpose of this library is to stream data from the ADS1299 to the computer, that's our focus, everything takes a back seat to that.

A bare board, not using the SD, accel, or aux data must have the following:

void loop() {
  if (board.streaming) {
    if (board.channelDataAvailable) {
      // Read from the ADS(s), store data, set channelDataAvailable flag to false


  // Check the serial port for new data
  if (board.hasDataSerial0()) {
    // Read one char and process it

The first if statement is only true if a b command is ran through the processChar function. The next if statement exploits a volatile interrupt driven boolean called channelDataAvailable. This interrupt driven system is new as of firmware version 2.0.0 a discussion of it can be found here. If the ADS1299 has signaled to the Board new data is ready, the function updateChannelData() is executed. This function will grab new data from the Board's ADS1299 (and from the daisy's ADS1299) and store that data to the arrays: lastBoardDataRaw, boardChannelDataRaw, meanBoardDataRaw, lastDaisyDataRaw, daisyChannelDataRaw, meanDaisyDataRaw, which can be accessed to drive filters or whatever your heart desires.

System Overview:

Sending Channel Data

In the OpenBCI system, and with most wireless systems, we are restricted by the rate at which we can send data.

If you send a packet from the Pic32 to the Device RFduino and you start it with 0x41, write 31 bytes, and follow with 0xCX (where X can be 0-F hex) then the packet will immediately be sent from the Device radio. This is counter to how if you want to send a message longer than 31 bytes (takes over two packets to transmit from Device radio to Host radio (Board to Dongle)) then you simply write the message, and that message will be sent in a multipacket format that allows it to be reassembled on the Dongle. This reassembling of data is critical to over the air programming.

Reference Guide:



Reads a status register to see if there is new accelerometer data.

Returns {boolean}

true if the accelerometer has new data.


Reads from the accelerometer to get new X, Y, and Z data. Updates the global array axisData.


The function the OpenBCI board will call in setup().


The function the OpenBCI board will call in setup. Turns sniff mode on and allows you to tap into the serial port that is broken out on the OpenBCI 32bit board.

You must alter Board_Defs.h file located:

On Mac:
/Users/username/Documents/Arduino/hardware/chipkit-core/pic32/variants/openbci/Board_Defs.h On Windows:


Specifically lines 311 and 313, change 7 and 10 to 11 and 12 for _SER1_TX_PIN and _SER1_RX_PIN respectively. Check out this sweet gif if you are a visual person

You will need to reflash your board! But now you can connect to pins 11 (TX) and 12 (RX) via any 3V3 serial to USB driver. Remember to use 3V3, 115200 baud, and have a common ground!


Called in every loop() and checks Serial0.

Returns {boolean}

true if there is data ready to be read.


Called in every loop() and checks Serial1.

Returns {boolean}

true if there is data ready to be read.


Process one char at a time from serial port. This is the main command processor for the OpenBCI system. Considered mission critical for normal operation.

character {char}

The character to process.

Returns {boolean}

true if the command was recognized, false if not.


If hasDataSerial0() is true then this function is called. Reads from Serial0 first and foremost, which comes from the RFduino. If no data is available then returns a 0x00 which is NOT a command that the system will recognize as a safe guard.

Returns {char}

The character from the serial port.


If hasDataSerial1() is true then this function is called. Reads from Serial1 which comes from the external serial port. If no data is available then returns a 0x00 which is NOT a command that the system will recognize as a safe guard.

Returns {char}

The character from the serial port.


Writes channel data, aux data, and footer to serial port or over wifi. Based on global variables useAux and useAccel Must keep for portability.

If curAccelMode is ACCEL_MODE_OFF then then sends data from auxData array and sets the contents of auxData to 0 after send. board.useAccel(false) If curAccelMode is ACCEL_MODE_ON then then sends data from axisData array and sets the contents of axisData to 0 after send. board.useAccel(true)


Called when the board ADS1299 has new data available. If there is a daisy module attached, that data is also fetched here.



Board mode changes the hardware pins.


0 - Board will operate leave all pins in default mode.


1 - Board will output serial debug data out of the external serial port.


2 - Board will read from A6 (D11), A7 (D12), and A8 (D13). A8 is only is use when there is no wifi present. The analog to digital converter is 10bits and the data will be in .

Pin Aux Bytes Notes
A6 0:1 D11
A7 2:3 D12
A8 4:5 D13 - If wifi not present


3 - Board will read from D11, D12, D13 (if wifi not present), D17, and D18 (if wifi not present).

Pin Aux Byte Notes
D11 0
D11 1
D13 2 If wifi not present
D17 3
D18 4 If wifi not present



0 - End of standard stream packet.


1 - End of stream packet with raw packet.


2 - End of stream packet, user defined.


3 - End of time sync up with accelerometer stream packet.


4 - End of time synced stream packet.


5 - End of time sync up stream packet.


6 - End of time synced stream packet.



0 - Sample rate 16000Hz


1 - Sample rate 8000Hz


2 - Sample rate 4000Hz


3 - Sample rate 2000Hz


4 - Sample rate 1000Hz


5 - Sample rate 500Hz


6 - Sample rate 250Hz

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