hsk_filter.h File Reference

HSK Filter generator. More...

#include <Infineon/XC878.h>
#include <string.h>

Include dependency graph for hsk_filter.h:

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Macros
#define	FILTER_FACTORY(prefix, valueType, sumType, sizeType, size)
	Generates a filter. More...
#define	FILTER_GROUP_FACTORY(prefix, filters, valueType, sumType, sizeType, size)
	Generates a group of filters. More...

Detailed Description

HSK Filter generator.

This file offers preprocessor macros to filter analogue values, by calculating the average of a set of a given length.

The buffer for the filter is stored in xdata memory.

Author

kami

Macro Definition Documentation

#define FILTER_FACTORY	(		prefix,
			valueType,
			sumType,
			sizeType,
			size
	)

Value:

\
/** Holds the buffer and its current state. */ \
struct { \
        /** The value buffer. */ \
        valueType values[size]; \
        /** The sum of the buffered values. */ \
        sumType sum; \
        /** The index of the oldest buffered value. */ \
        sizeType current; \
} xdata prefix; \
\
/** Initializes the buffer with 0. */ \
void prefix##_init(void) { \
        memset(&prefix, 0, sizeof(prefix)); \
} \
\
/** Updates the filter and returns the current sliding average of
buffered values.
@param value
        The value to add to the buffer
@return
        The average of the buffed values */ \
valueType prefix##_update(const valueType value) { \
        prefix.sum -= prefix.values[prefix.current]; \
        prefix.values[prefix.current++] = value; \
        prefix.sum += value; \
        prefix.current %= size; \
        return prefix.sum / size; \
} \

Generates a filter.

The filter can be accessed with:

• void <prefix>_init(void)
  • Initializes the filter with 0
• <valueType> <prefix>_update(const <valueType> value)
  • Update the filter and return the current average

Parameters

prefix	A prefix for the generated internals and functions
valueType	The data type of the stored values
sumType	A data type that can contain the sum of all buffered values
sizeType	A data type that can hold the length of the buffer
size	The length of the buffer

#define FILTER_GROUP_FACTORY	(		prefix,
			filters,
			valueType,
			sumType,
			sizeType,
			size
	)

Generates a group of filters.

The filters can be accessed with:

• void <prefix>_init(void)
  • Initializes all filters with 0
• <valueType> <prefix>_update(const ubyte filter, const <valueType> value)
  • Update the given filter and return the current average

Parameters

prefix	A prefix for the generated internals and functions
filters	The number of filters
valueType	The data type of the stored values
sumType	A data type that can contain the sum of all buffered values
sizeType	A data type that can hold the length of the buffer
size	The length of the buffer