#include "process.h"

Include dependency graph for process.c:

Macros
#define	NZEROS 2

#define	NPOLES 2

#define	GAIN_HP_2000 1.092933031f

#define	GAIN_N_2000 1.002243999f

#define	GAIN_HP_1000 1.045431062f

#define	GAIN_N_1000 1.004488020f

#define	GAIN_HP_500 1.194615832f

#define	GAIN_N_500 1.008976220f

Functions
float32_t	FilterHP (float32_t inData, unsigned char ch, uint32_t frequency)
	It filters a new sample applying a IIR high-pass filter in real time. More...

float32_t	FilterNOTCH (float32_t inData, unsigned char ch, uint32_t frequency)
	It filters a new sample applying a IIR notch filter in real time. More...

void	ResetFilterArrays (unsigned char nCh)
	Needed to reset the history of the filters and delete the previous states. More...

float32_t	FilterSample (float32_t inData, unsigned char filterIndex)
	It calls the routines for filtering a new sample. More...

void	UARTReceive4Bytes (uint32_t *ptr)
	This function can be used to easily handle the reception on the UART of 4bytes sized variables, e. g. float. More...

void	UARTSend4Bytes (unsigned char *ptr)
	This function can be used to easily handle the transmit on the UART of 4bytes sized variables, e. g. float. More...

void	UARTSend2Bytes (unsigned char *ptr)
	This function can be used to easily handle the transmit on the UART of 4bytes sized variables, e. g. int16. More...

void	UARTSendByte (unsigned char byte)
	This function can be used to easily handle the transmission on the UART of one byte. It is meant for the application of flow control. More...

Variables
const float32_t	lsbVolt = 0.000000536442f

float32_t	xv [NZEROS+1][8]

float32_t	yv [NZEROS+1][8]

float32_t	xvN [NPOLES+1][8]

float32_t	yvN [NPOLES+1][8]

volatile unsigned char	nChannels = 8

volatile unsigned char	filterEnable = 1

volatile float32_t	temperatureMCU = 0

volatile float32_t	batteryVoltage = 0

volatile float32_t	batteryTemperature = 0

volatile uint32_t	sF

Detailed Description

Source file of process module of the NEUROMOTUS project.

 ----------------— Function Description ---------------—
The process.c file contains all routines needed to properly
process the EMG signals acquired from the ADS1299. It includes
also helpful routines for communication.

 ----------------------— Updates ----------------------—

2015-10-01  /   Enzo Mastinu        / Creation

Function Documentation

§ FilterHP()

float32_t FilterHP	(	float32_t	inData,
		unsigned char	ch,
		uint32_t	frequency
	)

It filters a new sample applying a IIR high-pass filter in real time.

Parameters

[in]	inData	float input value
[in]	ch	index of the channel
[in]	frequency	is the sampling frequency

Returns: float filtered value.

Butterworth HP 2nd order @ 20Hz IIR Filter this function takes a float input and applies a real time filter process. The filter needs information about the previous states of input and output values, they are stored into xv[order+1][nChannels] and yv[order+1][nChannels] global arrays. The filters used are IIR:

from current input, past inputs and past outputs we generate the current value. In FIR you use only the current and past inputs. IIR parameters are calculated via Matlab: Fc = x; Wn = 20 / (Fc/2); Order = 2; [num den] = butter(Order, Wn, 'high'); we normalize the coefficients num = num/num(1) den = den/den(1) then, the coefficients the multiply the inputs are x0 * num(1), x1 * num(2), x2 * num(3) while for the outputs is y2 * den(1), y1 * den(2), y0 * den(3)

Measured Execution Time @80MHz: 13/07/2016 -> 1.31 us

§ FilterNOTCH()

float32_t FilterNOTCH	(	float32_t	inData,
		unsigned char	ch,
		uint32_t	frequency
	)

It filters a new sample applying a IIR notch filter in real time.

Parameters

[in]	inData	float input value
[in]	ch	index of the channel
[in]	frequency	is the sampling frequency

Returns: float filtered value.

Butterworth NOTCH 1st order @ 45-55 Hz IIR Filter this function takes a float input and applies a real time filter process. The filter needs information about the previous states of input and output values, they are stored into xvN[order+1][nChannels] and yvN[order+1][nChannels] global arrays. IIR parameters are calculated via Matlab: Fc = x; W0 = 50 / (Fc/2); Q = 35; Bw = W0/Q; [num den] = iirnotch(W0, Bw); we normalize the coefficients num = num/num(1) den = den/den(1) then, the coefficients the multiply the inputs are x0 * num(1), x1 * num(2), x2 * num(3) while for the outputs is y2 * den(1), y1 * den(2), y0 * den(3)

Measured Execution Time @80MHz: 13/07/2016 -> 1.38 us

§ FilterSample()

float32_t FilterSample	(	float32_t	inData,
		unsigned char	filterIndex
	)

It calls the routines for filtering a new sample.

Parameters

[in]	inData	float input value
[in]	filterIndex	index of the channel which the sample belongs

Returns: float output value.

This function contains the routines needed to apply digital filters to the data in a on-fly technique. This means that the latest acquired sample is passed through the filters and the filtered version is returned by this function.

Measured Execution Time @80MHz: 13/07/2016 -> 3 us

§ ResetFilterArrays()

void ResetFilterArrays ( unsigned char nCh )

Needed to reset the history of the filters and delete the previous states.

Parameters

[in] nCh number of channels

Returns: none.

Measured Execution Time @80MHz: 13/07/2016 -> 16 us

§ UARTReceive4Bytes()

void UARTReceive4Bytes ( uint32_t * ptr )

This function can be used to easily handle the reception on the UART of 4bytes sized variables, e. g. float.

Parameters

[in] *ptr points the variable to receive

Returns: none.

§ UARTSend2Bytes()

void UARTSend2Bytes ( unsigned char * ptr )

This function can be used to easily handle the transmit on the UART of 4bytes sized variables, e. g. int16.

Parameters

[in] *ptr points the variable to send

Returns: none.

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§ UARTSend4Bytes()

void UARTSend4Bytes ( unsigned char * ptr )

This function can be used to easily handle the transmit on the UART of 4bytes sized variables, e. g. float.

Parameters

[in] *ptr points the variable to send

Returns: none.

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§ UARTSendByte()

void UARTSendByte ( unsigned char byte )

This function can be used to easily handle the transmission on the UART of one byte. It is meant for the application of flow control.

Parameters

[in] byte to send

Returns: none.

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Macros

Functions

Variables

Detailed Description

Function Documentation

§ FilterHP()

§ FilterNOTCH()

§ FilterSample()

§ ResetFilterArrays()

§ UARTReceive4Bytes()

§ UARTSend2Bytes()

§ UARTSend4Bytes()

§ UARTSendByte()