Servo Interface Card (with Servo Control, Manual Override, Optical Input)

The Sensor Interface Card plugs on top of the Processor Card through two 44 pin connectors.  One connector is the digital signal interface.  The other connector is the analog signal and power interface.  The digital connector contains the serial UART connection to the GPS receiver, the GPS time mark signal, 8 buffered servo outputs (PWM signals), four amplified input counter signals, the standard Motorola Serial Peripheral Interface (SPI) lines from the Processor, 8 processor data bus lines and control (unused).

The analog connector carries 8 buffered high speed analog-to-digital signal lines (0 - 5 volts), a 2.5 volt reference, separate analog and digital grounds, separate analog power, and 17 uncommitted pins.

The card has 6 alternative inputs, complete with regulated 5 volt power, unregulated power, ground, reference voltage, and signal input lines.  These connection points allow the customer or Inertial Solutions the option to customize by connecting alternative gyro's or accelerometers as input to the analog-to-digital converter.

The Sensor Interface Card provides the separate analog and digital power regulation it requires.  A common DC power source in the range of 6 – 12 volts is shared across the analog connector by both Processor Card and Sensor Interface Card.  For example, a 7.2 volts 6 cell NiCad rechargeable battery pack rated at 1400 mili-amp hours provides 2+ hours operation for both cards.