cM44 Flexible DSP/Data Acquisition Platform

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• Overview

• Analog and Digital I/O Modules

• Telecom Modules

• Block Diagram

• Software Support

• About the Design and Manufacture of the cM44

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Overview

The cM44 board provides a flexible platform for a wide variety of DSP-based data acquisition applications. It represents an evolution of DSP-based "smart" data acquisition boards:

• a powerful but inexpensive 32-bit floating-point DSP

• cPCI bus controller for high-rate transfer/streaming of data to host RAM (up to 40 Mbyte per sec, depending on host system)

• small form factor

• flexible and expandable acquisition of real-world signals

The cPCI controller obviates the need for dual-port RAM or other complicated host interface circuitry, allowing more onboard area dedicated to number-crunching and data acquisition capability than with previous generations of boards, yet still consuming no more than half-size cPCI board space.

The cM44 baseboard is available in two (2) form factors:

• half-size cPCI (standard PC)

• 6U cPCI (Compact PCI)

Both cM44 board types include a 40 or 60 MHz TMS320C44 32-bit floating-point DSP controller, two banks of SRAM (local and global) which can each be 128k or 512k x 32 (total of 1M x 32 SRAM expansion), and 32-bit digital I/O. In addition the baseboard is low-cost; for example a 40 MHz board with 128k x 32 local SRAM is less than USD 1000, making it attractive for applications requiring DSP acceleration and high-rate cPCI bus-mastering data transfers.

cM44 Analog and Digital I/O Modules

The cM44 input/output philosophy is entirely modular, providing two (2) daughterboard sites for a wide array of "OMNIBUS" modules, including:

• A4D4   4-channel 16-bit 200 kHz SAR analog I/O with 6-pole anti-alias filters and 2-pole reconstruction filters, and software programmable gain; multiplex option available

• SD4   4-channel 24-bit 96 kHz sigma-delta analog I/O; 104 dB SNR typical

• SD16   16-channel 16-bit sigma-delta analog I/O, 82 dB SNR typical (no longer supported for M44; please see information about M67 board )

• S16-HS   High-Precision 16-channel 16-bit dc to 195 kHz sigma-delta input; high level of dc accuracy (no longer supported for M44; please see information about M67 board )

• A16D16   16-channel 16-bit 100 kHz SAR analog I/O with 2-pole antialias filters and 1-pole reconstruction filters (no longer supported for M44; please see information about M67 board )

• AIX   4-channel 16-bit 2.5 MHz SAR input, with anti-alias filters

• AIX20  4-channel 12-bit 20 MHz SAR input

• DAC40  4-ch 14-bit 40 MHz SAR output

Note that because the cM44 contains two (2) module sites, modules can be doubled to provide 2x channel capability (the numbers in parentheses above), and modules can also be mixed, to provide flexible data acquisition combinations.

cM44 Telecom Modules

The cM44 input/output philosophy is entirely modular, providing two (2) daughterboard sites for standard "OMNIBUS" telecom modules, including:

• TELCOM24  24-DSP telecom module with sigma-delta analog I/O option

cM44 Block Diagram

Below is a block diagram depiction of the cM44 and its architecture and components, including OMNIBUS module sites. Note that in any cases where the block diagram and specifications above disagree, the specifications above are correct:

cM44 Software Support

The cM44 board is supported by Signalogic off-the-shelf DSP software products designed for DSP-based data acquisition and C4x DSP code development. The software items listed below use VxD and kernel-mode device drivers developed by Signalogic, and provide support for the cM44 under Win9x, and WinXP:

Hypersignal®-Macro and Hypersignal-Acoustic software series, which offer a number of simulation and real-time instrument functions. Simulation functions include DSP and math functions, time domain display (including waterfall, contour, magnitude, unwrapped phase), difference equation, digital FIR and IIR filter design, sampling rate conversion, frequency zoom, wavelet transform, minimum phase calculation, and many more. Instrument functions include spectrum analyzer, digital oscilloscope, stimulus & response measurement, continuous signal generation, real-time "snap-in" filtering, continuous disk record and generate, and more.

DirectCore® is a Windows library which provides low-level and high-level calls for user-defined C/C++, Visual Basic, MATLAB®, or LabView® programs. DirectCore includes low-level cM44 board control functions such as reset/run/hold, register access, block memory transfer, DSP executable file download, etc. High-level functions include waveform file acquire/generate, continuous signal generation, and execution of any arbitrary Hypersignal DSP or math function. DirectDSP includes strip-chart recorder, digital oscilloscope and digital tape recorder demo program and source code examples.

The TMS320C4x Source Code Interface contains numerous C4x algorithms and functions in source and binary form, such as optimized FFTs, filters, matrix, transcendental, trig, signal manipulation function, cM44 board initialization and analog I/O examples, etc. These functions form the basis of higher-level software functions and instruments; modification can be used to customize Hypersignal or DirectDSP operation. User-defined C routine hooks are provided for real-time algorithm development. The C4x Source Code Interface can be used as a basic foundation for user-defined real-time DSP systems and products.

Real-Time Composer™ is a Windows program which offers a block-diagram based design environment that allows both block-diagram simulation and interactive display and instrument functions, including control over individual Hypersignal and MATLAB blocks. The DSPower-Real-Time Code Generator includes complete visual IDE for Texas Instruments development tools, and allows C source code generation from block diagram, with generated programs compiled and downloaded to the cM44 board for real-time execution.