Open Source Pmod Designs

August 23, 2020 - sam210723

The Pmod Standard developed by Digilent is a peripheral protocol, interconnect and form-factor guideline supported by various FPGA and microcontroller development boards. Digilent manufacture a wide variety of modules which conform to the Pmod standard. Some development boards which support the standard are listed below.

Board	Manufacturer	FPGA	Price	Buy
iCESugar	MuseLab	Lattice ICE40UP5K	$35 USD	MuseLab AliExpress Store
Mimas V2	Numato Lab	Xilinx XC6SLX9	$50 USD	Numato Lab Store
iCEBreaker	1BitSquared	Lattice iCE40UP5K	$65 USD	1BitSquared Store
ULX3S	Radiona	Lattice LFE5U-12F / LFE5U-85F	$115 / $155 USD	Radiona Crowd Supply Store
ECPIX-5	LambdaConcept	Lattice LFE5U-45F / LFE5U-85F	€99 / €149	LambdaConcept Store
Arty A7	Digilent	Xilinx XC7A35T / XC7A100T	$129 / $249 USD	Digilent Store

Designs

SFP Pmod

Interface for Small Form-factor Pluggable (SFP) modules

Small Form-factor Pluggable (SFP) Pmod

Small Form-factor Pluggable (SFP) transceivers typically convert bi-directional electrical signalling to a pair of optical fibres for transmission over long distances. These modules are commonly found in telecommunications and networking applications where they carry various protocols including Ethernet and Fibre Channel.

⚠ Some SFP modules are capable of drawing over 100mA ⚠

The Pmod standard assumes a maximum current draw per Pmod of 100mA. Check your development board is capable of supplying the required current through the Pmod connectors before plugging in a SFP module.

Downloads

EAGLE Schematic
PDF Schematic
EAGLE Board
PCB Gerbers
Octopart BOM

The PCB is a 4-layer impedance controlled board which uses the JLC7628 stackup and JLCPCB design rules. Project files and gerbers were built with Autodesk EAGLE 9.6.2.

Pinout

This module uses a single 12-pin 0.1" header to interface with the host board.

Pin	Name	Description
`TXD`	Transmit Data	Single-ended input to differential transmitter
`RXD`	Receive Data	Single-ended output of differential receiver
`LOS`	Loss of Signal	Active high output indicating optical power level is below receiver threshold.
`FLT`	Transmitter Fault	Active high output indicating low optical output at the transmitter. Toggling `DIS` will reset the transmitter to recover from the fault condition.
`DIS`	Transmitter Disable	Enable the transmitter by pulling this pin `LOW`. If left floating or `HIGH` the transmitter will be disabled.
`DET`	Module Detect	Pulled low by the SFP module after successful startup
`SDA`	Serial Data	Data line of two-wire diagnostic and monitoring (MOD_DEF) interface
`SCL`	Serial Clock	Clock line of two-wire diagnostic and monitoring (MOD_DEF) interface
`VCC`	Supply	Power supply from host board (3.3V DC)
`GND`	Ground	Common ground with host board

Schematic

Tested SFP Modules

Manufacturer / Model	Nominal Data Rate	Optical Wavelength	Lowest Stable Rate (50% duty cycle)
Cisco GLC-SX-MM	1.25 Gbps (1000BASE-SX 1GbE)	850 nm	50 kHz
Finisar FTLF8524P2BNL	1.062, 1.25, 2.125, 4.25 Gbps	850 nm	50 kHz