Particle PHOTON Users Manual
Photon Datasheet
Mode l numbe r: PHOTONH
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Photon Dat asheet v011
Contents
Photon Dat asheet
Contents
1. Functional description
1.1 Overview
1.2 Features
2. Interf aces
2.1 Po wer
2.2 RF
2.3 FCC Approved Antennas
2.4 Peripherals and GPIO
2.5 JTAG
2.6 External Coexistence Interf ace
3. Pin and butto n def inition
3.1 Pin markings
3.2 Pin description
3.3 Pin out diag rams
4. T echnical specification
4.1 Absolute maximum ratings
4.2 Recommended operating conditions
4.3 Wi-Fi Specificat ions
4.4 I/O Characteristics
5. Mechanical specifications
5.1 Dimensions and Weight
5.2 Mating connecto rs
5.3 Reco mmended pcb land pattern (Photon with headers)
5.4 Recommended pcb land pattern (Phot on without headers)
6. Layout
6.1 Photon v1.0.0 Top Layer (GTL)
6.2 Photon v1.0.0 GND Layer (G2L)
6.3 Photon v1.0.0 3V3 Layer (G15L)
6.4 Photon v1.0.0 Bottom Layer (GBL)
7. Recommended solder reflow prof ile
8. Bill of Materials
Build your own design based on the Photon!
9. Ordering informat ion
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10. Qualification and approvals
11. Product handling
11.1 Packaging
11.2 Moisture sensitivity levels
11.3 ESD Precautions
12. Def ault settings
13. Glossary
14. FCC IC CE Warnings and End Product Labeling Requirements
15. Revision history
16. Co ntact
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Photon Dat asheet v011
1. Functional description
1.1 Overview
Particle’s Internet of Things hardware development kit, the Photon, provides everything you need to build a
connected product. Part icle combines a powerf ul ARM Cortex M3 micro-controller with a Broadco m Wi-Fi chip in a tiny
thumbnail-sized module called the PØ (P-zero).
To get yo u start ed quickly, Particle adds a rock solid 3.3VDC SMPS power supply, RF and user interf ace components to
the PØ o n a small single-sided PCB called the Phot on. The design is open source, so when you’re ready to integ rate
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 Pho ton
plugs directly into standard breadboards and perf boards, and may also be mount ed with 0.1” pitch f emale headers on
a PCB. To minimize s pace required, the Phot on form f actor without headers has castellated edges. These make it
possible to surface mount the Photon directly onto your PCB.
1.2 Features
Particle PØ Wi-Fi module
Broadcom BCM43362 Wi-Fi chip
802.11b/g/n Wi-Fi
STM32F205 120Mhz ARM Cortex M3
1MB f lash, 128KB RAM
On-board RGB status LED (ext. drive provided)
18 Mixed-signal GPIO and advanced peripherals
Open so urce design
Real-time operating sys tem (FreeRTOS)
Sof t AP setup
FCC, CE and IC cert ified
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2. Interfaces
2.1 Power
Power to the Photo n is supplied via the on-board USB Micro B connector or directly via the VIN pin. If power is supplied
direct ly to the VIN pin, the voltag e sho uld be reg ulated bet ween 3.6VDC and 5.5VDC. When the Photon is powered via
the USB port, VIN will output a voltag e of approximat ely 4.8VDC due to a reverse polarity protection series scho ttky
diode between V+ of USB and VIN. When used as an output, the max load on VIN is 1A.
Typical current consumption is 80mA with a 5V input. Deep sleep quiescent current is 160uA. When powering the
Photon f rom t he USB connector, make sure to use a quality cable to minimize IR drops (current x resistance = voltage)
in the wiring. If a high resist ance cable (i.e., low current ) is used, peak currents drawn f rom the Photon when
transmitting and receiving will result in voltag e sag at the input which may cause a syst em brown out or intermittent
operation. Likewise, the power source should be suf f icient enough to source 1A of current to be on the saf e side.
2.2 RF
The RF sect ion of the Photo n is a f inely tuned impedance controlled network of component s that optimize the
ef ficiency and sensitivity of the Wi-Fi communications.
An RF feed line runs f rom t he PØ module into a SPDT RF-switch. Log ic level cont rol lines on the PØ module select which
of the t wo ports of the RF-switch is co nnected to the RF feed line. A 100pF decoupling capacito r is located on each
control line. One port is connected to a PCB ceramic chip antenna, and the other is co nnected to a u.FL connecto r f or
ext ernal antenna adaptation. The default port will be set to the chip antenna.
Additionally, a user API is available to switch bet ween internal, external and even an automatic mode which
continuously switches between each antenna and select s the bes t signal. All three RF ports on the RF-switch have a
10pF RF quality DC-blocking capacitor in series with them. These ef fectively pass 2.4 GHz f requencies f reely while
blocking unwanted DC voltag es f rom damag ing t he RF-switch. All RF traces are considered as tiny transmission lines
that have a contro lled 50 ohm impedance.
The chip antenna is impedance matched to the 50 o hm RF feed line via a Pi network comprised of three RF inductors (1
series, 2 shunt). Thes e values are quite specific to the Photon due to the PCB construct ion and layout of the RF
section. Even if the Photon’s layout design is copied exactly, to achieve the best perf ormance it would be wo rth reexamining the Pi network values on act ual samples of the PCB in question.
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2.3 FCC Approved Antennas
Ant enna T ype Manuf acture r MFG. Part # Gain
Dipole antenna LumenRadio 104 -1001 2.15dBi
Chip antenna Advanced Ceramic X AT7020-E3R0HBA 1.3dBi
2.4 Peripherals and GPIO
The Photon has to n of capability in a small foo tprint, with analog, digital and communication interf aces.
Peripheral Type Qty Input (I) / Out put (O) FT / 3V3
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
CAN 1 I/O FT
USB 1 I/O 3V3
PWM 9 O 3V3
Not es:
FT = 5.0V t olerant 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.
3V3 = 3.3V max pins.
PWM is available on D0, D1, D2, D3, A4, A5, WKP, RX, T X 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 t ime.
[1] [2 ]
3
[1]
[2 ]
[3 ]
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2.5 JTAG
Pin D3 throug h D7 are JTAG interf ace pins. These can be used to reprogram your Phot on bootloader or user f irmware
imag e with standard JTAG tools such as t he ST-Link v2, J-Link, R-Link, OLIMEX ARM-USB-TINI-H, and also the FTDI-based
Particle JTAG Prog rammer.
Photon Pin Description ST M32 Pin PØ Pin # PØ Pin Name De f ault Internal
D7 JTAG_TMS PA13 44 MICRO_JTAG_TMS ~40k pull-up
D6 JTAG_TCK PA14 4 0 MICRO_JTAG_TCK ~40k pull-down
D5 JTAG_TDI PA15 4 3 MICRO_JTAG_TDI ~40k pull-up
D4 JTAG_TDO PB3 41 MICRO_JTAG_TDO Floating
D3 JTAG_TRST PB4 42 MICRO_JTAG_TRSTN ~40k pull-up
3V3 Power
GND Ground
RST Reset
Not es:
Def ault state af ter reset f or a short period of time bef ore these pins are restored to GPIO (if JTAG debugging is not
required, i.e. USE_SWD_JT AG=y is not specified on the command line.
A standard 20-pin 0.1” shrouded male JTAG interface co nnector should be wired as f ollows:
[1]
[1]
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2.6 External Coexistence Interface
The Photon supports coexistence with Blueto oth and other external radios via the three g old pads o n the t op side of
the PCB near pin A3. These pads are 0.035” square, spaced 0.04 9” apart. This spacing supports the possibility of
tacking on a small 1.25mm - 1.27mm pitch 3-pin male header t o make it somewhat easier to interf ace with.
When two radios occupying the same f requency band are used in the same system, such as Wi-Fi and Bluetooth, a
coexistence interf ace can be used to coo rdinate 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 Bluetoo th priority status and TX/RX direction
3 BTCX_TXCONF 11 O Output g iving Bluetoot h permission to TX
When thes e pads are prog rammed to be used as a Bluetooth coexist ence interf ace, they’re set as high impedance on
power up and reset. Alternatively, they can be individually programmed to be used as GPIOs throug h sof tware control.
They can also be prog rammed to have an internal pull-up or pull-down resist or.
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3. Pin and button definition
3.1 Pin markings
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3.2 Pin description
Pin De script ion
VIN This pin can be used as an input or output. As an input, supply 3.6 to 5.5VDC t o power t he Photon. When the
Photon is powered via the USB port, t his pin will output a voltag e of approximat ely 4.8VDC due to a
reverse polarity prot ection series schottky diode between VUSB and VIN. When used as an output, t he max
load on VIN is 1A.
RST Act ive-low reset input. On-board circuitry cont ains 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 not present (1.65 to 3.6VDC).
3V3 T his pin is the out put of the o n-board reg ulator and is internally connected to the VDD of the WiFi module.
When powering the Photo n via VIN or the USB port, this pin will output a voltag e of 3.3VDC. This pin can
also be used to power the Phot on 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 disconnect ed from VIN and
USB.
WKP Active-high wakeup pin, wakes the module f rom 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.
A0~A9 12-bit Analog -to-Digital (A/D) inputs (0-4095), and also digital GPIOs. A6 and A7 are co de convenience
mappings, which means pins are not actually labeled as such but you may use code like analogRead(A7) .
A6 maps t o the DAC pin and A7 maps to the WKP pin.
DAC 12-bit Digital-to-Analog (D/A) out put (0-4 095), and also a digital GPIO. DAC is used as DAC1 in sof tware,
and A5 is a second DAC out put used as DAC2 in sof tware.
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.
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3.3 Pin out diagrams
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