SwiftModule-PX: SwiftADC Analog-to-Digital for SwiftModule

SwiftADC consists of a reference design, driver and extension board that makes it easy to add analog input capability to a SwiftModule-based product design.

The SwiftADC design is based on an Analog Devices AD7689 8-channel and 16-bit precision ADC chip which is connected to the Windows CE system via SPI protocol. The SwiftModule host SPI controller can run at up to 13Mbps which means that high sample rates can be supported, up to 250K samples per second.

An extension board plugs directly into the SwiftKit's extension header so that the A to D capability is immediately available to users as part of the development kit. The supplied schematics mean that the design can be incorporated into the final production baseboard.

The AD7689 converter
The AD7689 is an 8-channel, 16-bit, charge redistribution successive approximation register (SAR) analog-to-digital converter (ADC) that operates from a single power supply, VDD.

The AD7689 contains all components for use in a multichannel, low power data acquisition systems, including a true 16-bit SAR ADC with no missing codes; a 8-channel, low crosstalk multiplexer useful for configuring the inputs as single ended (with or without ground sense), differential, or bipolar; an internal low drift reference (selectable 2.5 V or 4.096 V) and buffer; a temperature sensor; a selectable one-pole filter; and a sequencer that is useful when channels are continuously scanned in order.

The AD7689 uses a simple SPI interface for writing to the configuration register and receiving conversion results. The SPI interface uses a separate supply, VIO, which is set to the host logic level. Power dissipation scales with throughput.

Each AD7689 is housed in a tiny 20-lead LFCSP with operation specified from −40°C to +85°C.

Further information:

Main SwiftModule product page
SwiftLite-PX Development Kit
SwiftKit Development System
Custom Baseboards for SwiftModule
SwiftGSM cellular modem for SwiftModule
SwiftGPS Global Positioning System for SwiftModule
SwiftModule minisite with online forum and FAQ
Download a SwiftModule datasheet
www.swiftmodule.com