SparkFun Photon RedBoard

The SparkFun Photon RedBoard is a complete Wi-Fi enabled development platform for creating connected devices with ease. The Photon RedBoard has been based around the P1 Particle Module. The I/O, USB, and power connectors are all broken out to a familiar Arduino shape.

The P1 (P-one) is Particle’s tiny Wi-Fi module that contains both the Broadcom BCM43362 Wi-Fi chip and a reprogrammable STM32F205RGY6 32-bit ARM Cortex M3 microcontroller.

SparkFun Photon RedBoard Device

SparkFun Photon RedBoard. Copyright SparkFun Electronics

In addition to having 1MB of internal flash memory for storing the firmware, the SparkFun Photon also features 128KB of Ram, 1MB of extra SPI flash and 120 MHz of clock.


All the reported information are extracted from the official SparkFun Photon RedBoard reference page, visit this page for more details and updates.

Pin Mapping

SparkFun Photon Pin Map

SparkFun Photon RedBoard Official Schematic, Reference Design & Pin Mapping are available on the official SparkFun Photon datasheet page.

Flash Layout

The internal flash of the SparkFun Photon RedBoard is organized into sectors of different size according to the following table:

Start address Size Content
0x8000000 16Kb BootLoader
0x8004000 16Kb DCT1
0x8008000 16Kb DCT2
0x800C000 16Kb EEPROM1
0x8010000 64Kb EEPROM2
0x8020000 128kb Virtual Machine
0x8040000 128kb Bytecode Bank 0
0x8060000 128kb Bytecode Bank 1
0x8080000 128kb Bytecode Bank 2
0x80A0000 128kb Bytecode Bank 3
0x80C0000 128kb Bytecode Bank 4
0x80E0000 128kb Bytecode Bank 5


To avoid deleting the SparkFun Photon configuration it is recommended not to write in sectors between 0x8004000 and 0x8020000.


If internal flash is used in a Zerynth program, it is recommended to start from pages at the end of flash (bytecode bank 5) towards the virtual machine, to minimize the chance of clashes. Since writing to a sector entails erasing it first, the write operation can be slow even for small chunks of data, depending on the size of the chosen sector.

Device Summary

  • Microcontroller: ARM 32-bit Cortex™-M3 CPU Core
  • Operating Voltage: 3.3V
  • Input Voltage: 3.6-6V
  • Digital I/O Pins (DIO): 24
  • Analog Input Pins (ADC): 5
  • Analog Outputs Pins (DAC): 2
  • UARTs: 2
  • SPIs: 3
  • I2Cs: 1
  • CANs: 1
  • Flash Memory: 1MB
  • SRAM: 128 KB
  • Extra Flash Memory: 1MB
  • Clock Speed: 120Mhz
  • Size (LxW mm): 36.58 X 20.32


Power to the SparkFun Photon device is supplied via the on-board USB micro B connector or directly via the VIN pin:

  • If power is supplied directly to the VIN pin, the voltage should be regulated between 3.6VDC and 5.5VDC.
  • If the device is powered via the USB port, VIN will output a voltage of approximately 4.8VDC due to a reverse polarity protection series schottky diode between V+ of USB and VIN.


When used as an output, the max load current on VIN is 1 Ampere.

Typical current consumption is 80mA with a 5V input. Deep sleep quiescent current is 160uA. When powering the SparkFun Photon from the USB connector, make sure to use a quality cable to minimize voltage drops. If a high resistance cable (i.e., low current) is used, peak currents drawn from the SparkFun Photon when transmitting and receiving will result in voltage sag at the input which may cause a system brown out or intermittent operation. Likewise, the power source should be sufficient enough to source 1A of current to be on the safe side.

Connect, Register, Virtualize and Program

On Windows machines (Windows 10), the SparkFun Photon RedBoard in Standard Mode is automatically recognized as Virtual Serial port; otherwise Particle USB Drivers for SparkFun Photon are required by Zerynth Studio for accessing the serial port establishing a connection with the STM32 UART.

To install the drivers on Windows plug the SparkFun Photon on an USB port, download the *.exe package, and follow the installation steps to complete the operation.


It could be necessary to temporarily disable the digitally signed driver enforcement policy of Windows to allow driver installation. There are good instructions on how to do that in this guide.

On MAC OSX and Linux platforms USB drivers are not required.


For Linux Platform: to allow the access to serial ports the user needs read/write access to the serial device file. Adding the user to the group, that owns this file, gives the required read/write access:

  • Ubuntu distribution –> dialout group
  • Arch Linux distribution –> uucp group

If the device is still not recognized or not working, the following udev rules may need to be added:

#SparkFun Photon
SUBSYSTEMS=="usb", ATTRS{idVendor}=="2b04", ATTRS{idProduct}=="d008", MODE="0666", GROUP="users", ENV{ID_MM_DEVICE_IGNORE}="1"
SUBSYSTEMS=="tty", ATTRS{idVendor}=="2b04", ATTRS{idProduct}=="d008", MODE="0666", GROUP="users", ENV{ID_MM_DEVICE_IGNORE}="1"
SUBSYSTEMS=="usb", ATTRS{idVendor}=="2b04", ATTRS{idProduct}=="c008", MODE="0666", GROUP="users", ENV{ID_MM_DEVICE_IGNORE}="1"
SUBSYSTEMS=="tty", ATTRS{idVendor}=="2b04", ATTRS{idProduct}=="c008", MODE="0666", GROUP="users", ENV{ID_MM_DEVICE_IGNORE}="1"

Once connected on a USB port, if drivers have been correctly installed, the SparkFun Photon RedBoard can be seen as Virtual Serial port and it is automatically recognized by Zerynth Studio and listed in the Device Management Toolbar as “SparkFun Photon RedBoard DFU Mode” if the device is in DFU Mode, otherwise as “SparkFun Photon RedBoard”.

To register and virtualize a Photon RedBoard, it is necessary to put the device in DFU Mode (Device Firmware Upgrade).


On Windows machines it is necessary to install also the SparkFun Photon DFU drivers for virtualizing the device.

The official Particle Core DFU driver and the related installation procedure are reported here but they also work for SparkFun Photon RedBoard.

Follow these steps to register and virtualize a Photon RedBoard:

  • Put the SparkFun Photon in DFU Mode (Device Firmware Upgrade):
    • Hold down BOTH buttons (reset and mode);
    • Release only the reset button, while holding down the mode button;
    • Wait for the LED to start flashing magenta, then yellow;
    • Release the mode button; the device is now in DFU Mode (yellow blinking led);
  • Select the SparkFun Photon on the Device Management Toolbar;
  • Register the device by clicking the “Z” button from the Zerynth Studio;
  • Create the unique Zerynth Virtual Machine for the connected device by clicking the “Z” button for the second time;
  • Virtualize the device by clicking the “Z” button for the third time.


During these operations the SparkFun Photon device must be in DFU Mode. if the device returns in standard mode, it is necessary to put it in DFU Mode again

After virtualization, the SparkFun Photon is ready to be programmed and the Zerynth scripts uploaded. Just Select the virtualized device from the “Device Management Toolbar” and click the dedicated “upload” button of Zerynth Studio and reset the device by pressing the Reset on-board button when asked.


To exploit the Wi-Fi chip functionalities of the SparkFun Photon, the lib.broadcom.bcm43362 library must be installed and imported on the Zerynth script.

Firmware Over the Air update (FOTA)

The Firmware Over the Air feature allows to update the device firmware at runtime. Zerynth FOTA in the SparkFun Photon device is available for bytecode.

Flash Layout is shown in table below:

Start address Size Content
0x08020000 128Kb VM Slot 0
0x08040000 384kb Bytecode Slot 0
0x080A0000 384kb Bytecode Slot 1


FOTA Record (small segment of memory where the current and desired state of the firmware is store) for the SparkFun Photon device is allocated in 16kb DCT1 (see Flash Layout) sector at 0x08006000 address.

Power Management and Secure Firmware

Power Management feature allows to optimize power consumption by putting the device in low consumption state.

Secure Firmware feature allows to detect and recover from malfunctions and, when supported, to protect the running firmware (e.g. disabling the external access to flash or assigning protected RAM memory to critical parts of the system).

Both these features are strongly platform dependent; more information at Power Management - STM32F section and Secure Firmware - STM32F section.