User's Manual

P440 Data Sheet / User Guide DRAFT 29

Fig. 15h: User Serial pinouts

4.3 Powering and Grounding the Unit

4.3.1 Powering the P440 through the USB Power Jack vs Locking &

Mezzanine Connectors

The P440 is provided in Development Kits or Labs as a “Kit Radio” and individually as an “Industrial

Module.” The difference between the two is a configuration option. P440s provided as Kit Radios

are powered through the USB Power jack (J13). P440s provided as Industrial Modules can be

powered either through the Locking connector (J11) or the User Mezzanine connector (J10). Kit

Radios cannot be powered through the Locking or User Mezzanine connectors and Industrial

Modules cannot be powered though the USB Power jack.

This is a safety feature intended to insure that the user cannot accidentally connect power through the

Locking connector at voltages as high as 48 volts while simultaneously connecting power through the

USB Power jack at 5 volts. Allowing this to happen would put both the P440 and any computer

connected to the USB Data jack at risk of severe damage.

4.3.2 Reverse polarity protection

The power input (VCC_Main) is reverse polarity-protected and can be driven by any voltage between

4.5 and 48 volts.

4.3.3 Two means of Powering the P440

There are two techniques for supplying power to the P440. One can connect and disconnect the

power connectors or one can power the board continuously and use the Power_Enable_H pin on the

J10 User Mezzanine connector to turn on and off the P440 main power regulators. This capability

gives the user the opportunity to do a hard reboot of the board without needing to physically break a

connection.

J7 – User

Serial Header

J4 - Reserved

Header

Pin 1