Diamond-MM has a full set of features to support a wide range of analog and digital I/O application requirements. The analog input circuit uses a 12-bit A/D converter and can be configured for single-ended or differential input wiring, as well as unipolar or bipolar input ranges. It also offers 10 different input ranges, so it can work with a wide variety of input signals. The maximum A/D conversion rate is approximately 2,000-20,000 per second using interrupts (depending on the operating system).

Two analog outputs provide 12-bit resolution over a 0-5V or user-adjustable output range with 8mA drive current and 4uS settling time. The D/A can also be used as a digital attenuator for an analog signal fed into one of the reference inputs.

The board contains 8 digital inputs and 8 digital outputs. It has an on-board 82C54 counter/timer chip to control the A/D sampling rate and provide general purpose counting functions.

Analog Input Ranges

Diamond-MM supports multiple analog input voltage ranges, including both unipolar (+ only) and bipolar (+ and) ranges. In addition, a gain amplifier circuit allows you to reduce the input range to handle smaller signals.

To get the best resolution, select the smallest input range that is large enough to cover the entire range of your input signals. You can also install a resistor to customize the range exactly to your requirements. Note: On any A/D converter, the input range is the same as the full-scale A/D range divided by the gain. On Diamond-MM, the full-scale A/D range is 0-5V in unipolar mode and ±5V in bipolar mode.

Analog Output Ranges

The full-scale analog output voltage range is unipolar and is preset to 0 - 5V. However, you can adjust this range anywhere from 0 - 4V to 0 - 10V by adjusting a potentiometer on the board. You can also supply an external reference signal to each DAC individually to select unique ranges for each output channel. If the reference signal is an AC waveform (e.g. an audio signal), then the DAC can be used as an attenuator (volume control).

Note: The -NA versions of Diamond-MM do not have analog outputs.

A/D Conversion Methods and Rates

To provide flexibility in integrating with your application, Diamond-MM offers several methods of controlling A/D conversions. An A/D conversion can be triggered in 3 different ways: software command, external trigger, or on-board pacer clock. After the conversion is done, the data can be transferred from the board to system memory in 3 ways: software command, interrupt routine, or DMA transfer. Different conversion rates require the use of different transfer ethods:

Free Software

Diamond-MM comes with free driver software compatible with C and Basic anguages. Example programs are included to get you started quickly. Some examples of the supported board operations are:

• A/D conversion on single channel
• A/D conversion scan on multiple channels
• Interrupt-based A/D conversions
• DMA A/D conversions
• Analog output on single channel
• Analog output on both channels
• Program counter/timers
• Digital input, bit and byte
• Digital output, bit and byte

I/O Header Pinout