CDSP

Process output from ADC peripherals of Infineon AURIX TC4x

Since R2024a

• 

Libraries:
Embedded Coder Support Package for Infineon AURIX TC4x Microcontrollers / AURIX TC4x

Description

The CDSP block applies signal processing techniques to digital data coming from the DSADC block (using the on-chip modulator or external modulator (EXMOD)), TMADC block, or general purpose (GP) registers. Based on the filter properties and the filter chain that you specify in the Converter Digital Signal Processing (CDSP) block, the block outputs the filtered data as 16-bit signed and unsigned integers.

When you enable the timestamp output, the block provides an additional output port to read the timestamp as a 16-bit unsigned value.

Ports

Input

primary input — Input data from DSADC block, EXMOD, TMADC block, or GP registers

scalar

The port accepts incoming data from the DSADC block, EXMOD, TMADC block, or GP registers and applies different signal processing techniques based on the application. For the DSADC block, you must set the Result type parameter to Counts because the CDSP block accepts data in counts. For GP registers, the block accepts data from Simulink^® source blocks such as the Repeating Sequence Stair block.

Note

• In a code generation workflow, the port accepts data from the DSADC block, EXMOD, TMADC block, or GP registers.

• In a simulation workflow, the port accepts data from any Simulink source block with discrete output.

Data Types: uint16 | int16

secondary input — Input data to use in Math filter block

scalar

The port accepts incoming data from the DSADC block, EXMOD, TMADC block, or GP registers and uses this secondary input data for addition or subtraction with CDSP secondary input in the Math filter block. For the DSADC block, you must set the Result type parameter to Counts because the CDSP block accepts data in counts.

Dependencies

To enable this port, set the DSP filter chain parameter to Advanced average 1 (FC1), Basic data accumulation (FC2), or Advanced average 2 (FC4). Any of these options adds a Math tab, where you must set the Math operation parameter to Addition with CDSP secondary input or subtraction with CDSP secondary input

Data Types: uint16 | int16

Output

filtereddata — 16-bit filtered data

vector

The block outputs the filtered data as 16-bit values in the form of an N-by-1 array. N varies based on the timestamp, number of output samples, and FIFO depth configuration.

The size of the output depends on the values of the other parameters in the block.

Enable FIFO	Enable timestamp output	Number of output samples	FIFO depth	Size of filtereddata
Disable	Disable	NA	NA	1-by-1
	Enable	NA	NA	1-by-1
Enable	Disable	1	4	4-by-1
			3	3-by-1
			2	2-by-1
			1	1-by-1
		2	4	4-by-1
			2	2-by-1
	Enable	1	4	3-by-1
			3	2-by-1
			2	1-by-1
		2	4	3-by-1

If the FIR coefficients do not change, the CDSP block uses the default filter coefficients when you set the DSP Filter chain parameter to Demo FIR (FC0) in the Block Parameters dialog box.

Note

To avoid data type conversion errors while using the block, make sure to set the output and input data of the same type.

This table shows the results from the accumulation filter when you provide a constant input to the CDSP block and set the DSP Filter chain parameter to Demo FIR (FC0) with default coefficients. The block populates the default coefficient values in the Coefficients parameter.

CDSP Input	Output Data Type	Accumulation Filter Results	Result Description
int16(100)	int16	100
int16(32767)	int16	32767
int16(0)	int16	0
int16(-32768)	int16	-32768
uint16(100)	uint16	32768	100 + 32768 = 32868, CDSP block reports the lower 16 bits of the result
uint16(65535)	uint16	32767	65535 + 32768 = 98303, CDSP block reports the lower 16 bits of 98303 (32767)
uint16(0)	uint16	32768	0 + 32768 = 32768, CDSP block reports the lower 16 bits of the result
uint16(32767)	uint16	65535	32767 + 32768 = 65535, CDSP block reports the lower 16 bits of the result
uint16(32768)	uint16	0	326768 + 32768 = 65536, CDSP block reports the lower 16 bits of the result

You can observe from the table that when the data type of the output data is uint16, the CDSP hardware adds 32768 (2^15) to the output result. For example, assume that the CDSP hardware outputs a 1000 0000 0000 0000 (16-bit value). If you set the output data type to int16, the result from the accumulation filter is -32767 ((-2^15 * 1) + (2^14 * 0) + (2^13 * 0) + ….. + (2^0 * 0)). When you set the output data type to uint16, the result from the accumulation filter is 32768 ((2^15 * 1) + (2^14 * 0) + (2^13 * 0) + ….. + (2^0 * 0)).

Data Types: uint16 | int16

timestamp — Timestamp of 16-bit counter value

scalar

The port outputs the status of the 16-bit counter value of the timestamp counter.

Dependencies

To enable this port, select the Enable timestamp output parameter.

Data Types: uint16

Parameters

Filter Config

Enable timestamp output — Option to enable timestamp output

off (default) | on

Select this parameter to configure the timestamp output port.

Selecting this parameter enables options in the Timestamp tab and Timestamp event (under Events tab) in the CDSP Peripheral Configuration.

Note

As the timestamp is always associated with the trigger, it is recommended that you configure and provide the trigger accordingly, when the timestamp is enabled. Otherwise, the FIFO functionality does not work, as timestamp is flushed into FIFO first and then to the result registers.

DSP Filter chain — Option to select filter chain

Demo FIR (FC0) (default) | Advanced average 1 (FC1) | Basic data accumulation (FC2) | Advanced median (FC3) | Advanced average 2 (FC4) | Basic AURIX (FCM)

Select the filter chain to be used by the CDSP block.

• Demo FIR (FC0) — Select this option to use the finite impulse response (FIR) filter block.

• Advanced average 1 (FC1) — Select this option to use the filter blocks in the predefined sequence of FIR > sixth-order infinite impulse response filter (IIR6) > Math filter (MAT) > Average filter (AVG).

• Basic data accumulation (FC2) — Select this option to use the filter blocks in the predefined sequence of FIR > IIR6 > MAT > Data accumulation filter (DA).

• Advanced median (FC3) — Select this option to use the filter blocks in the predefined sequence of FIR > IIR6 > Median filter (MDN).

• Advanced average 2 (FC4) — Select this option to use the filter blocks in the predefined sequence of IIR6 > FIR > MAT > AVG.

• Basic AURIX (FCM) — Select this option to use the filter blocks in the predefined sequence of FIR > first-order infinite impulse response filter (IIR1) > DA.

The block adds the FIR, IIR6, IIR1, MAT, AVG, and DA tabs in the block parameters dialog box, depending on the choice of the DSP filter chain parameter. You can set the parameters of the filter block in these tabs.

Output datatype — Data type of filtered output

int16 (default) | uint16

Select the data type of the filtered output.

Filter Config > FIFO Configuration

Enable FIFO — Option to enable FIFO register

off (default) | on

Select this parameter to enable first-in first-out (FIFO) register.

Elements to retrieve from FIFO — Output samples to read from FIFO

1 (default) | 2

Configure whether to read a single sample or double samples at a time.

Selecting 2 helps in fetching the data faster from the FIFO.

Dependencies

To enable this parameter, select the Enable FIFO parameter.

FIFO depth — FIFO register depth

4 (default) | 3 | 2 | 1 (only if Enable Timestamp is not selected)

Specify the FIFO level after which the module generates service request.

Dependencies

To view this parameter, select the Enable FIFO parameter.

FIR

Bypass FIR block — Option to bypass FIR block in the filter chain

off (default) | on

Select this parameter to bypass the FIR block in the filter chain.

Coefficients — Coefficients of FIR filter

[8, 13, -39, -130, -170, -135, -68, 27, 220, 424, 400, 124, -268, -617, -763, -604, -74, 655, 1244, 1419, 971, -26, -1390, -2569, -2842, -1783, 736, 4316, 8296, 11711, 13682, 13682, 11711, 8296, 4316, 736, -1783, -2842, -2569, -1390, -26, 971, 1419, 1244, 655, -74, -604, -763, -617, -268, 124, 400, 424, 220, 27, -68, -135, -170, -130, -39, 13, 8] (default) | scalar in the range (-32767 to 32767) | vector in the range (-32767 to 32768)

Specify the FIR filter coefficients of a size ranging from 1-by-1 to 1-by-128.

Dependencies

To enable this parameter, disable the Bypass FIR block parameter.

Decimation rate — Ratio of input data rate to output data rate in FIR filter

1 (default) | 2 | 4 | 8 | 16

Specify the ratio of input data rate to output data rate in the FIR filter.

Note

• In a code generation workflow, the block supports a decimation rate ranging from 1 to 16.

• In a simulation workflow, the block supports a decimation rate of 1.

Dependencies

To enable this parameter, disable the Bypass FIR block parameter.

IIR6

Bypass IIR6 block — Option to bypass IIR6 filter block in filter chain

off (default) | on

Select this parameter to bypass the IIR6 filter block in the filter chain.

Coefficients — Coefficients of IIR6 filter

[16384, 0, 0, 16384, 0, 0, 16384, 0, 0, 16384, 0, 0, 16384, 0, 0, 16384, 0, 0] (default) | vector in the range (-32767 to 32768)

Specify the 1-by-18 filter coefficients in the sequence of [a₀₀, a₀₁, a₀₂, a₁₀, a₁₁, a₁₂, a₂₀, a₂₁, a₂₂, b₀₀, b₀₁, b₀₂, b₁₀, b₁₁, b₁₂, b₂₀, b₂₁, b₂₂] for the IIR6 filter with the transfer function:

$$\frac{b_{00}+b_{01}{z}^{-1}+b_{02}{z}^{-2}}{a_{00}+a_{01}{z}^{-1}+a_{02}{z}^{-2}}\times \frac{b_{10}+b_{11}{z}^{-1}+b_{12}{z}^{-2}}{a_{10}+a_{11}{z}^{-1}+a_{12}{z}^{-2}}\times \frac{b_{20}+b_{21}{z}^{-1}+b_{22}{z}^{-2}}{a_{20}+a_{21}{z}^{-1}+a_{22}{z}^{-2}}$$

Dependencies

To enable this parameter, disable the Bypass IIR6 block parameter.

Decimation rate — Ratio of input data rate to output data rate in IIR6 filter

1 (default) | 2 | 4 | 8 | 16

Specify the ratio of input data rate to output data rate in the IIR6 filter.

Note

• In a code generation workflow, the block supports a decimation rate ranging from 1 to 16.

• In a simulation workflow, the block supports a decimation rate of 1.

Dependencies

To enable this parameter, disable the Bypass IIR6 block parameter.

Bit extension — Number of bits to shift in input and output data of IIR6 filter block

0 (default) | scalar in the range (0, 7)

Specify the number of bits to shift in the IIR6 filter block to improve precision.

Dependencies

To enable this parameter, disable the Bypass IIR6 block parameter.

Math

Bypass math block — Option to bypass Math filter block in filter chain

off (default) | on

Select to bypass Math filter block in the filer chain.

Math operation — Option to select mathematical operation

Addition with constant (default) | Addition with CDSP secondary input | Subtraction with constant | Subtraction with CDSP secondary input | Multiplication with constant

Specify the mathematical operation for the Math filter.

If you choose the Addition with CDSP secondary input or Subtraction with CDSP secondary input, the CDSP block adds an input port for the secondary input.

Dependencies

To enable this parameter, disable the Bypass math block parameter.

Constant value (-32768 to 32767) — Option to provide constant value for mathematical operation

0 (default) | scalar in the range (-32768 to 32767)

Specify the constant value to use in the Math filter.

Dependencies

To enable this parameter, disable the Bypass math block parameter and set the Math operation parameter to Addition with constant, Subtraction with constant, or Multiplication with constant.

Bit shift after math operation (-32 to 32) — Number of bits for arithmetic right-shift on the Math filtered output

0 (default) | scalar in the range (-32 to 32)

Specify the number of bits for arithmetic right-shift operation on the Math filtered output to correct the output in case of overflow.

Dependencies

To enable this parameter, disable the Bypass math block parameter.

Average

Bypass avegare block — Option to bypass AVG filter block in the filter chain

off (default) | on

Select this parameter to bypass AVG filter block in the filer chain.

Number of samples — Option to select the number of samples for averaging operation

1 (default) | 2 | 4 | 8 | 16 | 32 | 64 | 128

Specify the number of samples to consider for the averaging operation.

Dependencies

To enable this parameter, disable the Bypass average block parameter.

Median

Bypass median block — Option to bypass MDN filter block in filter chain

off (default) | on

Select this parameter to bypass the MDN filter block in the filter chain.

Number of samples — Option to select the number of samples median operation

1 (default) | 3 | 5 | 7 | 9

Specify the number of samples to consider for the median filter.

Dependencies

To enable this parameter, disable the Bypass median block parameter.

IIR1

Bypass IIR1 block — Option to bypass IIR1 filter block in filter chain

off (default) | on

Select this parameter to bypass the IIR1 filter block in the filter chain.

Dependencies

To enable this parameter, disable the Bypass IIR1 block parameter.

Coefficients — Coefficients of IIR6 filter

[16384, -12288, 16384, -16384] (default) | vector in the range (-32767 to 32768)

Specify the 1-by-4 filter coefficients in the sequence of [a₀, a₁, b₀, b₁] for the IIR1 filter with transfer function:

$$\frac{b_0+b_1{z}^{-1}}{a_0+a_1{z}^{-1}}$$

Dependencies

To enable this parameter, disable the Bypass IIR1 block parameter.

DA

Bypass DA block — Option to bypass DA filter block in filter chain

off (default) | on

Select this parameter to bypass the DA filter block in the filter chain.

Disable this parameter to configure data accumulation parameters in the Integrator Control tab in CDSP Peripheral Configuration tool.

Samples in accumulation cycle — Option to select number of data samples per accumulation cycle

1 (default) | scalar in the range (1, 512)

Specify the number of data samples per accumulation cycle.

Dependencies

To enable this parameter, disable the Bypass DA block parameter.

Samples to discard — Option to select number of data samples to discard during accumulation process

0 (default) | scalar in the range (0, 63)

Specify the number of data samples to discard during the accumulation process.

Dependencies

To enable this parameter, disable the Bypass DA block parameter.

Adjust gain by right shift on DA result — Option to select number of bits for right shift operation on data accumulation filter result

0 (default) | scalar in the range (0, 10)

Specify the number of bits to use for a right shift operation on the DA result for gain adjustment.

Dependencies

To enable this parameter, disable the Bypass DA block parameter.

Disable filter chain restart — Option to disable restarting all filter blocks before DA filter block

off (default) | on

Select this parameter to disable the restarting of all the filter blocks prior to DA filter block in the selected filter chain.

Dependencies

To enable this parameter, disable the Bypass DA block parameter.

Version History

Introduced in R2024a