Information

Digilent Pmod™ Interface Specification

www.digilentinc.com page 4 of 11

Host Peripheral

0.45"

0.20"

Right angle female

connector

Right angle male

connector

Fig 2: Standard Twelve-Pin Connector Placement

The connection standard for system boards that provide I

C connectors is to use a 2x4 male, 100 mil

spaced, pin header connector with straight pins. This connector is generally not near a board edge, as

the intent is to use cable connections rather than directly plugging the module into the connector. The

connector provides two sets of the I

C signals, power and ground, so that the I

C bus can be formed

by daisy chaining system boards or Pmods. The system board can either be the root of one or two

daisy chains, or in the middle of a daisy chain.

Pmods with I

C interfaces will also have a 2x4 pin header connector so that the module can be

included in a daisy chain of modules and system boards. The I

C connector can either be a right

angle male connector at the board edge if reason to restrict overall module height or a straight male

connector anywhere on the board if there is no reason to restrict module height. Some modules have

both an SPI and an I

C interface. In this case the SPI interface will appear on a 2x6 right angle male

connector conforming to the above placement conventions, and the I

C interface will appear on a 2x4

straight male connector inboard from the board edge.

The following diagram shows basic PCB dimensions, physical connector placement and pin

numbering conventions for the module circuit boards intended to make use of Pmod clips or for direct

connection to system boards. Note that the connector is offset from the center of the board. This

offset allows I

C modules to be plugged into Pmod connectors on some boards with the appropriate

pin offset so that the power and ground pins will mate appropriately and keep the module within the

same geometry as a Pmod.