The ColdFire® DSP Library contains digital signal processing algorithms optimized for the ColdFire architecture. These algorithms are implemented directly in assembly for computational efficiency and then encapsulated into a simple C interface. In addition, a large number of predefined and pretested filter configurations are provided in order to reduce the need for a user to design digital filters.
The library is designed to enable embedded sensor applications with basic signal processing functionality, but without the need for a DSP co-processor. By taking advantage of an on-chip multiply-accumulate unit (MAC), a ColdFire microcontroller can efficiently execute DSP algorithms.
|Shape||lowpass, highpass, bandpass, notch||Shape of frequency response, i.e., are high frequencies passed through or attenuated|
|Order||2,3,4,5,6||Rolloff steepness. Higher orders roll off faster but require more MCU bandwidth|
|Cutoff||varies by order, most cover 0.20-0.80 range in 0.05 increments||Digital cutoff frequency (-3dB). Related to analog frequency by sample rate,|
The following table identifies all filter configurations included in the library. Each combination of filter shape, order and cutoff constitutes a single filter configuration. Each configuration comes with four parameters – filter coefficients array, numerator scale factor, denominator scale factor, and filter order. The configurations below are all characterized as Butterworth IIR filters.
|Shape||Order||Minimum Cutoff||Cutoff Increment||Maximum Cutoff|