Photon Datasheet (v014)


void setup() {
    Particle.publish("my-event","The internet just got smarter!");

Functional description


Particle's Internet of Things hardware development kit, the Photon, provides everything you need to build a connected product. Particle combines a powerful ARM Cortex M3 micro-controller with a Broadcom Wi-Fi chip in a tiny thumbnail-sized module called the PØ (P-zero).

To get you started quickly, Particle adds a rock solid 3.3VDC SMPS power supply, RF and user interface components to the PØ on a small single-sided PCB called the Photon. The design is open source, so when you're ready to integrate the Photon into your product, you can.

The Photon comes in two physical forms: with headers and without. Prototyping is easy with headers as the Photon plugs directly into standard breadboards and perfboards, and may also be mounted with 0.1" pitch female headers on a PCB. To minimize space required, the Photon form factor without headers has castellated edges. These make it possible to surface mount the Photon directly onto your PCB.


  • Particle PØ Wi-Fi module
    • Broadcom BCM43362 Wi-Fi chip
    • 802.11b/g/n Wi-Fi
    • STM32F205RGY6 120Mhz ARM Cortex M3
    • 1MB flash, 128KB RAM
  • On-board RGB status LED (ext. drive provided)
  • 18 Mixed-signal GPIO and advanced peripherals
  • Open source design
  • Real-time operating system (FreeRTOS)
  • Soft AP setup
  • FCC, CE and IC certified


Block Diagram


Power to the Photon 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. When the Photon 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 on VIN is 1A.

Typical average current consumption is 80mA with 5V @ VIN with Wi-Fi on. Deep sleep quiescent current is typically 80uA (Please refer to Recommended Operating Conditions for more info). When powering the Photon from the USB connector, make sure to use a quality cable to minimize IR drops (current x resistance = voltage) in the wiring. If a high resistance cable (i.e., low current) is used, peak currents drawn from the 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.


The RF section of the Photon is a finely tuned impedance controlled network of components that optimize the efficiency and sensitivity of the Wi-Fi communications.

An RF feed line runs from the PØ module into a SPDT RF-switch. Logic level control lines on the PØ module select which of the two ports of the RF-switch is connected to the RF feed line. A 100pF decoupling capacitor is located on each control line. One port is connected to a PCB ceramic chip antenna, and the other is connected to a u.FL connector for external antenna adaptation. The default port will be set to the chip antenna.

Additionally, a user API is available to switch between internal, external and even an automatic mode which continuously switches between each antenna and selects the best signal. All three RF ports on the RF-switch have a 10pF RF quality DC-blocking capacitor in series with them. These effectively pass 2.4GHz frequencies freely while blocking unwanted DC voltages from damaging the RF-switch. All RF traces are considered as tiny transmission lines that have a controlled 50 ohm impedance.

The chip antenna is impedance matched to the 50 ohm RF feed line via a Pi network comprised of three RF inductors (1 series, 2 shunt). These values are quite specific to the Photon due to the PCB construction and layout of the RF section. Even if the Photon's layout design is copied exactly, to achieve the best performance it would be worth re-examining the Pi network values on actual samples of the PCB in question.

FCC Approved Antennas

Antenna Type Manufacturer MFG. Part # Gain
Dipole antenna LumenRadio 104-1001 2.15dBi
Chip antenna Advanced Ceramic X AT7020-E3R0HBA 1.3dBi

Peripherals and GPIO

The Photon has ton of capability in a small footprint, with analog, digital and communication interfaces.

Peripheral Type Qty Input(I) / Output(O) FT[1] / 3V3[2]
Digital 18 I/O FT/3V3
Analog (ADC) 8 I 3V3
Analog (DAC) 2 O 3V3
SPI 2 I/O 3V3
I2S 1 I/O 3V3
I2C 1 I/O FT
USB 1 I/O 3V3
PWM 93 O 3V3


[1] FT = 5.0V tolerant pins. All pins except A3 and DAC are 5V tolerant (when not in analog mode). If used as a 5V input the pull-up/pull-down resistor must be disabled.

[2] 3V3 = 3.3V max pins.

[3] PWM is available on D0, D1, D2, D3, A4, A5, WKP, RX, TX with a caveat: PWM timer peripheral is duplicated on two pins (A5/D2) and (A4/D3) for 7 total independent PWM outputs. For example: PWM may be used on A5 while D2 is used as a GPIO, or D2 as a PWM while A5 is used as an analog input. However A5 and D2 cannot be used as independently controlled PWM outputs at the same time.


Pin D3 through D7 are JTAG interface pins. These can be used to reprogram your Photon bootloader or user firmware image with standard JTAG tools such as the ST-Link v2, J-Link, R-Link, OLIMEX ARM-USB-TINI-H, and also the FTDI-based Particle JTAG Programmer. If you are short on available pins, you may also use SWD mode which requires less connections.

Photon Pin JTAG SWD STM32F205RGY6 Pin PØ Pin # PØ Pin Name Default Internal[1]
D5 JTAG_TDI PA15 43 MICRO_JTAG_TDI ~40k pull-up
3V3 Power Power
GND Ground Ground
RST Reset Reset

Notes: [1] Default state after reset for a short period of time before these pins are restored to GPIO (if JTAG debugging is not required, i.e. USE_SWD_JTAG=y is not specified on the command line.)

A standard 20-pin 0.1" shrouded male JTAG interface connector should be wired as follows:

External Coexistence Interface

The Photon supports coexistence with Bluetooth and other external radios via the three gold pads on the top side of the PCB near pin A3. These pads are 0.035" square, spaced 0.049" apart. This spacing supports the possibility of tacking on a small 1.25mm - 1.27mm pitch 3-pin male header to make it somewhat easier to interface with.

When two radios occupying the same frequency band are used in the same system, such as Wi-Fi and Bluetooth, a coexistence interface can be used to coordinate transmit activity, to ensure optimal performance by arbitrating conflicts between the two radios.

Pad # PØ Pin Name PØ Pin # I/O Description
1 BTCX_RF_ACTIVE 9 I Signals Bluetooth is active
2 BTCX_STATUS 10 I Signals Bluetooth priority status and TX/RX direction
3 BTCX_TXCONF 11 O Output giving Bluetooth permission to TX

When these pads are programmed to be used as a Bluetooth coexistence interface, they're set as high impedance on power up and reset.

Memory Map

STM32F205RGY6 Flash Layout Overview

  • Bootloader (16 KB)
  • DCT1 (16 KB), stores Wi-Fi credentials, keys, mfg info, system flags, etc..
  • DCT2 (16 KB), swap area for DCT1
  • EEPROM emulation bank 1 (16 KB)
  • EEPROM emulation bank 2 (64 KB) [only 16k used]
  • System firmware (512 KB) [256 KB Wi-Fi/comms + 256 KB hal/platform/services]
  • Factory backup, OTA backup and user application (384 KB) [3 x 128 KB]

DCT Layout

The DCT area of flash memory has been mapped to a separate DFU media device so that we can incrementally update the application data. This allows one item (say, server public key) to be updated without erasing the other items.

DCT layout as of v0.4.9 found here in firmware

Region Offset Size
system flags 0 32
version 32 2
device private key 34 1216
device public key 1250 384
ip config 1634 128
claim code 1762 63
claimed 1825 1
ssid prefix 1826 26
device id 1852 6
version string 1858 32
dns resolve 1890 128
reserved1 2018 64
server public key 2082 768
padding 2850 2
flash modules 2852 100
product store 2952 24
antenna selection 2976 1
cloud transport 2977 1
alt device public key 2978 128
alt device private key 3106 192
alt server public key 3298 192
alt server address 3490 128
reserved2 3618 1280

Note: Writing 0xFF to offset 34 (DEFAULT) or 3106 (ALTERNATE) will cause the device to re-generate a new private key on the next boot. Alternate keys are currently unsupported on the Photon but are used on the Electron as UDP/ECC keys. You should not need to use this feature unless your keys are corrupted.

// Regenerate Default Keys
echo -e "\xFF" > fillbyte && dfu-util -d 2b04:d006 -a 1 -s 34 -D fillbyte
// Regenerate Alternate Keys
echo -e "\xFF" > fillbyte && dfu-util -d 2b04:d006 -a 1 -s 3106 -D fillbyte

Memory Map (Common)

Region Start Address End Address Size
Bootloader 0x8000000 0x8004000 16 KB
DCT1 0x8004000 0x8008000 16 KB
DCT2 0x8008000 0x800C000 16 KB
EEPROM1 0x800C000 0x8010000 16 KB
EEPROM2 0x8010000 0x8020000 64 KB

Memory Map (Modular Firmware - default)

Region Start Address End Address Size
System Part 1 0x8020000 0x8060000 256 KB
System Part 2 0x8060000 0x80A0000 256 KB
User Part 0x80A0000 0x80C0000 128 KB
OTA Backup 0x80C0000 0x80E0000 128 KB
Factory Backup 0x80E0000 0x8100000 128 KB

Memory Map (Monolithic Firmware - optional)

Region Start Address End Address Size
Firmware 0x8020000 0x8080000 384 KB
Factory Reset 0x8080000 0x80E0000 384 KB
Unused (factory reset modular) 0x80E0000 0x8100000 128 KB

Pin and button definition

Pin markings

Pin description

Pin Description
VIN This pin can be used as an input or output. As an input, supply 3.6 to 5.5VDC to power the Photon. When the Photon is powered via the USB port, this pin will output a voltage of approximately 4.8VDC due to a reverse polarity protection series Schottky diode between VUSB and VIN. When used as an output, the max load on VIN is 1A.
RST Active-low reset input. On-board circuitry contains a 1k ohm pull-up resistor between RST and 3V3, and 0.1uF capacitor between RST and GND.
VBAT Supply to the internal RTC, backup registers and SRAM when 3V3 is not present (1.65 to 3.6VDC).
3V3 This pin is the output of the on-board regulator and is internally connected to the VDD of the Wi-Fi module. When powering the Photon via VIN or the USB port, this pin will output a voltage of 3.3VDC. This pin can also be used to power the Photon directly (max input 3.3VDC). When used as an output, the max load on 3V3 is 100mA. NOTE: When powering the Photon via this pin, ensure power is disconnected from VIN and USB.
WKP Active-high wakeup pin, wakes the module from sleep/standby modes. When not used as a WAKEUP, this pin can also be used as a digital GPIO, ADC input or PWM.
D0~D7 Digital only GPIO pins. D0~D3 may also be used as a PWM output.
A0~A7 12-bit Analog-to-Digital (A/D) inputs (0-4095), and also digital GPIOs. A6 and A7 are code convenience mappings, which means pins are not actually labeled as such but you may use code like analogRead(A7). A6 maps to the DAC pin and A7 maps to the WKP pin. A4,A5,A7 may also be used as a PWM output.
DAC 12-bit Digital-to-Analog (D/A) output (0-4095), and also a digital GPIO. DAC is used as DAC or DAC1 in software, and A3 is a second DAC output used as DAC2 in software.
RX Primarily used as UART RX, but can also be used as a digital GPIO or PWM.
TX Primarily used as UART TX, but can also be used as a digital GPIO or PWM.

In addition to the 24 pins around the outside of the Photon, there are 7 pads on the bottom the Photon PCB that can be used to connect to extra signals: RGB LED outputs, SETUP button, SMPS enable line and USB D+/D-. Photon Pins #25-31 are described in the Pin out diagrams. Also refer to the Recommended PCB land pattern photon without headers section for their location on the bottom of the Photon.

Pin out diagrams

Technical specification

Absolute maximum ratings

Parameter Symbol Min Typ Max Unit
Supply Input Voltage VVIN-MAX +6.5 V
Supply Output Current IVIN-MAX-L 1 A
Supply Output Current I3V3-MAX-L 100 mA
Storage Temperature Tstg -40 +85 °C
Enable Voltage VEN VVIN+0.6 V
ESD Susceptibility HBM (Human Body Mode) VESD 2 kV
Parameter Symbol Min Typ Max Unit
Supply Input Voltage VVIN +3.6 +5.5 V
Supply Input Voltage V3V3 +3.0 +3.3 +3.6 V
Supply Output Voltage VVIN +4.8 V
Supply Output Voltage V3V3 +3.3 V
Supply Input Voltage VVBAT +1.65 +3.6 V
Supply Input Current (VBAT) IVBAT 19 uA
Operating Current (Wi-Fi on) IVIN avg 80 100 mA
Operating Current (Wi-Fi on) IVIN pk 235[1] 430[1] mA
Operating Current (Wi-Fi on, w/powersave) IVIN avg 18 100[2] mA
Operating Current (Wi-Fi off) IVIN avg 30 40 mA
Sleep Current (5V @ VIN) IQs 1 2 mA
Deep Sleep Current (5V @ VIN) IQds 80 100 uA
Operating Temperature Top -20 +60 °C
Humidity Range Non condensing, relative humidity 95 %


[1] These numbers represent the extreme range of short peak current bursts when transmitting and receiving in 802.11b/g/n modes at different power levels. Average TX current consumption in will be 80-100mA.

[2] These are very short average current bursts when transmitting and receiving. On average if minimizing frequency of TX/RX events, current consumption in powersave mode will be 18mA

Wi-Fi Specifications

Feature Description
WLAN Standards IEEE 802 11b/g/n
Antenna Port Single Antenna
Frequency Band 2.412GHz -- 2.462GHz (United States of America and Canada)
2.412GHz -- 2.472GHz (EU/Japan)
Sub Channels 1 -- 11 (United States of America and Canada)
1 -- 13 (EU/Japan)
Modulation DSSS, CCK, OFDM, BPSK, QPSK, 16QAM, 64QAM
PØ module Wi-Fi output power Typ. Tol. Unit
RF Average Output Power, 802.11b CCK Mode 1M Avail. upon request +/- 1.5 dBm
11M - +/- 1.5 dBm
RF Average Output Power, 802.11g OFDM Mode 6M - +/- 1.5 dBm
54M - +/- 1.5 dBm
RF Average Output Power, 802.11n OFDM Mode MCS0 - +/- 1.5 dBm
MCS7 - +/- 1.5 dBm

I/O Characteristics

These specifications are based on the STM32F205RGY6 datasheet, with reference to Photon pin nomenclature.

Parameter Symbol Conditions Min Typ Max Unit
Standard I/O input low level voltage VIL -0.3 0.28*(V3V3-2)+0.8 V
I/O FT[1] input low level voltage VIL -0.3 0.32*(V3V3-2)+0.75 V
Standard I/O input high level voltage VIH 0.41*(V3V3-2)+1.3 V3V3+0.3 V
I/O FT[1] input high level voltage VIH V3V3 > 2V 0.42*(V3V3-2)+1 5.5 V
VIH V3V3 ≤ 2V 0.42*(V3V3-2)+1 5.2 V
Standard I/O Schmitt trigger voltage hysteresis[2] Vhys 200 mV
I/O FT Schmitt trigger voltage hysteresis[2] Vhys 5% V3V3[3] mV
Input/Output current max Iio ±25 mA
Input/Output current total Iio total ±120 mA
Input leakage current[4] Ilkg GND ≤ Vio ≤ V3V3 GPIOs ±1 µA
Input leakage current[4] Ilkg RPU Vio = 5V, I/O FT 3 µA
Weak pull-up equivalent resistor[5] RPU Vio = GND 30 40 50 k Ω
Weak pull-down equivalent resistor[5] RPD Vio = V3V3 30 40 50 k Ω
I/O pin capacitance CIO 5 pF
DAC output voltage (buffers enabled by default) VDAC 0.2 V3V3-0.2 V
DAC output resistive load (buffers enabled by default) RDAC 5 k Ω
DAC output capacitive load (buffers enabled by default) CDAC 50 pF


[1] FT = Five-volt tolerant. In order to sustain a voltage higher than V3V3+0.3 the internal pull-up/pull-down resistors must be disabled.

[2] Hysteresis voltage between Schmitt trigger switching levels. Based on characterization, not tested in production.

[3] With a minimum of 100mV.

[4] Leakage could be higher than max. if negative current is injected on adjacent pins.

[5] Pull-up and pull-down resistors are designed with a true resistance in series with switchable PMOS/NMOS. This PMOS/NMOS contribution to the series resistance is minimum (~10% order).

Mechanical specifications

Dimensions and Weight

Headers Dimensions in inches (mm) Weight
With 1.44 x 0.8 x 0.27 (36.58 x 20.32 x 6.86) 5 grams
Without 1.44 x 0.8 x 0.17 (36.58 x 20.32 x 4.32) 3.7 grams

Mating connectors

The Photon (with headers) can be mounted with (qty 2) 12-pin single row 0.1" female headers. Typically these are 0.335" (8.5mm) tall, but you may pick a taller one if desired. When you search for parts like these it can be difficult to navigate the thousands of parts available online so here are a few good choices for the Photon:

Description MFG MFG Part Number Distributor
12-pin 0.1" Female Header (Tin) Sullins Connector Solutions PPTC121LFBN-RC Digikey
12-pin 0.1" Female Header (Gold) Sullins Connector Solutions PPPC121LFBN-RC Digikey
12-pin 0.1" Female Header (Tin) Harwin M20-7821246 Mouser

You may also use other types, such as reverse mounted (bottom side SMT) female headers, low profile types, etc..

The Photon (with headers) can be mounted with 0.1" 12-pin female header receptacles using the following PCB land pattern:

A Photon with headers part for EAGLE can be found in the Particle EAGLE library

The Photon (without headers) can be surface mounted directly in an end application PCB using the following PCB land pattern:

In addition to the 24 pins around the outside of the Photon, there are 7 pads on the bottom the Photon PCB that can be used to connect to extra signals: RGB LED outputs, SETUP button, SMPS enable line and USB D+/D-. Photon Pins #25-31 are described in the Pin out diagrams.

Solder mask around exposed copper pads should be 0.1mm (4 mils) larger in all directions. E.g., a 0.08" x 0.10" pad would have a 0.088" x 0.108" solder mask.

A Photon without headers part for EAGLE can be found in the Particle EAGLE library


Schematic - USB

Schematic - Power

Schematic - User I/O

Schematic - RF

Schematic - PØ Wi-Fi Module


Photon v1.0.0 Top Layer (GTL)

Photon v1.0.0 GND Layer (G2L)

Photon v1.0.0 3V3 Layer (G15L)

Photon v1.0.0 Bottom Layer (GBL)

Phase Temperatures and Rates
A-B. Ambient~150°C, Heating rate: < 3°C/s
B-C. 150~200°C, soak time: 60~120 s
C-D. 200~245°C, Heating rate: < 3°C/s
D. Peak temp.: 235~245°C, Time above 220°C: 40~90 s
D-E. 245~220°C, Cooling rate: < 1°C/s

Bill of Materials

Build your own design based on the Photon!

Qty Device Minimum Specification Package/Case Part Designator MFG. MFG. PN
1 ANTENNA 2.4GHz Ceramic 5.0mm × 2.0mm x 2.6mm ANT1 Advanced Ceramic X AT7020-E3R0HBA
2 CERAMIC CAPACITOR 22uF Ceramic 6.3V 10% X5R 0603 C4,C5 Samsung CL10A226MQ8NRNC
6 CERAMIC CAPACITOR 0.1uF Ceramic 6.3V 10% X5R 0402 C6,C7,C8,C11,C12,C16 RongFu 0402B104K01A
2 CERAMIC CAPACITOR 100pF Ceramic 6.3V 10% X5R 0402 C2,C3 Fenghua 0402CG101J500NT
4 CERAMIC CAPACITOR 10uF Ceramic 6.3V 10% X5R 0603 C9,C11,C13,C15 Sumsung CL10A106MQ8NNNC
3 CERAMIC CAPACITOR (RF) 10pF Ceramic 6.3V 10% X5R 0402 C1,C14,C17 Murata GJM1555C1HR80BB01D
1 CONNECTOR USB Micro-B w/tabs & slots USB-MICROB X1 Kaweei CMCUSB-5BFM2G-01-D
1 CONNECTOR uFL Connector SMD X2 Kaweei P1163-0140R
2 HEADER Single String 1.2" Mating Length 0.1" 12-pin JP1,JP2 Kaweei CP25411-12G-S116-A
1 DIODE Diode Schottky 30V 3A DO-220AA D1 Vishay SS3P3-M3/84A
1 DIODE (LED) Blue SMD 0603 LED1 Everlight 19-217/BHC-ZL1M2RY/3T
1 DIODE (LED) LED RGB Common Anode Diffused SMD 4-PLCC (2.0mm x 2.0mm) LED2 Cree CLMVB-FKA-CFHEHLCBB7A363
1 INDUCTOR 2.2uH 1.5A 3mm x 3mm L4 Taiyo Yuden NR3015T2R2M
1 INDUCTOR (RF) 3.9nH RF inductor 0402 L3 Johanson L-07C3N9SV6T
1 INDUCTOR (RF) 4.7nH RF inductor 0402 L1 Johanson L-07C4N7SV6T
1 INDUCTOR (RF) 6.8nH RF inductor 0402 L2 Johanson L-07C6N8JV6T
1 WI-FI + MCU Broadcom Wi-FI + STM32F205RGY6 MCU Custom USI SMD U1 USI WM-N-BM-09-S
1 RF SWITCH RF Switch SPDT UQFN-6 (1x1mm) U3 Skyworks SKY13350-385LF
1 POWER REGULATOR 3.3V 1.5MHz 600mA High Efficiency PWM Step-Down DC/DC Converter SOT23-5 U2 Richtek RT8008-33GB
1 RESISTOR 100k 5% 0402 R4 Fenghua RC-02W104FT
2 RESISTOR 22R 5% 0402 R5,R6 Fenghua RC-02W220JT
1 RESISTOR 10k 5% 0402 R8 Fenghua RC-02W103JT
4 RESISTOR 1k 5% 0402 R1,R2,R3,R7 Fenghua RC-02W102JT
2 SWITCH Button 160gf 3.6mm x 3.1mm SETUP,RESET Haoyu TS-1185A-C

Ordering information

Photons are available from in single quantities with and without headers, and also included in different maker kits.

Qualification and approvals

Photon with Headers

  • Model Number: PHOTONH
  • RoHS
  • CE
  • IC: 20127-PHOTON

Photon without Headers

  • Model Number: PHOTONNOH
  • RoHS
  • CE
  • IC: 20127-PHOTON

Product handling


The Photon comes in two primary styles of packaging: Matchbox and Kit Box. The matchbox packaging contains the bare essentials to get you started, while the Photon Kit contains a breadboard, Micro B USB cable, sticker, prototyping card and a couple sensors to build your first Internet connected project!

Photons without headers in matchbox packaging are also available in JEDEC style trays for automated pick and place machines. Request more details from us on this in the Contact section below.

Moisture sensitivity levels

The Moisture Sensitivity Level (MSL) relates to the packaging and handling precautions required. The PØ module on the Photons dominate the MSL requirements and are rated level 3. In general, this precaution applies for Photons without headers. If reflowing a Photon directly onto an application PCB, increased moisture levels prior to reflow can damage sensitive electronics on the Photon. A bake process to reduce moisture may be required.

For more information regarding moisture sensitivity levels, labeling, storage and drying see the MSL standard see IPC/JEDEC J-STD-020 (can be downloaded from

ESD Precautions

The photon contains highly sensitive electronic circuitry and is an Electrostatic Sensitive Device (ESD). Handling a photon without proper ESD protection may destroy or damage it permanently. Proper ESD handling and packaging procedures must be applied throughout the processing, handling and operation of any application that incorporates photons. ESD precautions should be implemented on the application board where the photon is mounted. Failure to observe these precautions can result in severe damage to the photon!

Default settings

The Photon comes preprogrammed with a bootloader and a user application called Tinker. This application works with an iOS and Android app also named Tinker that allows you to very easily toggle digital pins, take analog and digital readings and drive variable PWM outputs.

The bootloader allows you to easily update the user application via several different methods, USB, OTA, Serial Y-Modem, and also internally via the Factory Reset procedure. All of these methods have multiple tools associated with them as well.

You may use the online Web IDE Particle Build to code, compile and flash a user application OTA (Over The Air). Particle Dev is a local tool that uses the Cloud to compile and flash OTA as well. There is also a package Spark DFU-UTIL for Particle Dev that allows for Cloud compiling and local flashing via DFU over USB. This requires dfu-util to be installed on your system. 'dfu-util' can also be used with Particle CLI for Cloud compiling and local flashing via the command line. Finally the lowest level of development is available via the GNU GCC toolchain for ARM, which offers local compile and flash via dfu-util. This gives the user complete control of all source code and flashing methods. This is an extensive list, however not exhaustive.


Switched-Mode Power Supply
Radio Frequency
The edge of the PCB has plated holes that are cut in half which resemble the top of a castle. These make it easy to solder the Photon down to another PCB with a SMT reflow process.
Surface Mount Technology (often associated with SMD which is a surface mount device).
Access Point
Light-Emitting Diode
Red green and blue LEDs combined and diffused in one package.
Universal Serial Bus
Quiescent current
Current consumed in the deepest sleep state
Five-tolerant; Refers to a pin being tolerant to 5V.
+3.3V; The regulated +3.3V supply rail. Also used to note a pin is only 3.3V tolerant.
Real Time Clock
Over The Air; describing how firmware is transferred to the device.

FCC IC CE Warnings and End Product Labeling Requirements

Federal Communication Commission Interference Statement This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one of the following measures:

  • Reorient or relocate the receiving antenna.
  • Increase the separation between the equipment and receiver.
  • Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
  • Consult the dealer or an experienced radio/TV technician for help.

FCC Caution: Any changes or modifications not expressly approved by the party responsible for compliance could void the user's authority to operate this equipment. This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions:

  1. This device may not cause harmful interference, and
  2. This device must accept any interference received, including interference that may cause undesired operation.

FCC Radiation Exposure Statement: This equipment complies with FCC radiation exposure limits set forth for an uncontrolled environment. This transmitter module must not be co-located or operating in conjunction with any other antenna or transmitter. This End equipment should be installed and operated with a minimum distance of 20 centimeters between the radiator and your body.

IMPORTANT NOTE: In the event that these conditions can not be met (for example certain laptop configurations or co-location with another transmitter), then the FCC authorization is no longer considered valid and the FCC ID can not be used on the final product. In these circumstances, the OEM integrator will be responsible for re-evaluating the end product (including the transmitter) and obtaining a separate FCC authorization.

End Product Labeling The final end product must be labeled in a visible area with the following:


Manual Information to the End User The OEM integrator has to be aware not to provide information to the end user regarding how to install or remove this RF module in the user’s manual of the end product which integrates this module.

Canada Statement This device complies with Industry Canada’s licence-exempt RSSs. Operation is subject to the following two conditions:

  1. This device may not cause interference; and
  2. This device must accept any interference, including interference that may cause undesired operation of the device.

Le présent appareil est conforme aux CNR d’Industrie Canada applicables aux appareils radio exempts de licence.

L’exploitation est autorisée aux deux conditions suivantes:

  1. l’appareil ne doit pas produire de brouillage;
  2. l’utilisateur de l’appareil doit accepter tout brouillage radioélectrique subi, même si le brouillage est susceptible d’en compromettre le fonctionnement.

Caution Exposure: This device meets the exemption from the routine evaluation limits in section 2.5 of RSS102 and users can obtain Canadian information on RF exposure and compliance. Le dispositif répond à l'exemption des limites d'évaluation de routine dans la section 2.5 de RSS102 et les utilisateurs peuvent obtenir des renseignements canadiens sur l'exposition aux RF et le respect.

The final end product must be labelled in a visible area with the following: The Industry Canada certification label of a module shall be clearly visible at all times when installed in the host device, otherwise the host device must be labelled to display the Industry Canada certification number of the module, preceded by the words “Contains transmitter module”, or the word “Contains”, or similar wording expressing the same meaning, as follows:

Contains transmitter module IC: 20127-PHOTON

This End equipment should be installed and operated with a minimum distance of 20 centimeters between the radiator and your body. Cet équipement devrait être installé et actionné avec une distance minimum de 20 centimètres entre le radiateur et votre corps.

The end user manual shall include all required regulatory information/warning as shown in this manual.

Revision history

Revision Date Author Comments
- 30-March-2015 BW Initial release
v003 7-April-2015 BW Updated template
v004 8-April-2015 BW Updated Overview, Block diagram, Power, RF, and Pin markings sections
v005 9-April-2015 BW Updated BOM
v006 21-April-2015 BW Added JTAG, BT CO-EX, I/O Characteristics, Schematic, Layout, Reflow Profile, Glossary, Updated Operating Conditions
v007 28-April-2015 BW Added Layout, Updated analog pins, Land patterns, Packaging, Mating Connectors
v008 11-May-2015 BW Updated BT CO-EX, PWM info, Qualifications
v009 31-May-2015 BW Updated Pinouts, DAC info, Height dimensions, Solder mask info, Recommended operating conditions
v010 1-June-2015 BW Updated VBAT info
v011 24-July-2015 BW Added FCC IC CE Warnings and End Product Labeling Requirements, Updated power output, added approved antennas, Corrected DAC2 as A3, Added pin numbers to PCB Land Pattern for Photon without headers.
v012 15-January-2016 WH Added TELEC Certification information and expanded explanation of Photons with and without headers.
v013 7-April-2016 BW Added: full STM32 part number, Memory map, DAC limits, SWD pin locations, max source/sink current, more descriptive info about bottom side pads, known errata URL. Updated: BT COEX info, pin diagram, block diagram, operating conditions, pin descriptions, land-pattern image signal keepout note.
v014 13-September-2016 BW Updated Mating connectors section.

Known Errata

We are tracking known errata with this datasheet here. These issues/errors in the datasheet will be resolved in subsequent revisions.



Community Forums