F2807x/F2837xD/F2837xS/F28004x/F28003x/F2838x SDFM

Configure filter channel for SDFM Module

• Library:

• Embedded Coder Support Package for Texas Instruments C2000 Processors / F2807x

  Embedded Coder Support Package for Texas Instruments C2000 Processors / F2837xD

  Embedded Coder Support Package for Texas Instruments C2000 Processors / F2837xS

  Embedded Coder Support Package for Texas Instruments C2000 Processors / F28004x

  Embedded Coder Support Package for Texas Instruments C2000 Processors / F28003x

  Embedded Coder Support Package for Texas Instruments C2000 Processors / F2838x/ C28x

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Description

The sigma delta filter module (SDFM) is a four-channel digital filter designed specifically for current measurement and resolver position decoding in motor control applications. Each input channel can receive an independent delta-sigma (ΔΣ) modulator bit stream. The bit streams are processed by four individually-programmable digital decimation filters.

The filter set includes a fast comparator (secondary filter) for immediate digital threshold comparisons for over-current and under-current monitoring and a primary data filter.

Each SDFM module consists of:

• Four independent configurable primary filter (data filter) units.

• Four independent, configurable secondary filter (comparator) units.

• Eight external pins (four sigma-delta data input pins and four sigma-delta clock input pins).

• Four different configurable modulator clock modes.

For more information on configuring filter channels, refer to SDFM Configuration Parameters.

Ports

Output

DFSTS — Data filter status

0 | 1 | -1

Status of the data filter returned as one of the following:

• 0 - Data filter not ready

• 1 - Data filter ready

• -1 - Modulator clock failure

DFLTX — Data filter

scalar

The primary filter data output. It is represented in either a 32-bit or a 16-bit format.

DFLTX - x represents the filter channel.

CFSTS — Comparator Status

0 | 1 | 2 | 3 | 4 | 5 | -1

The comparator status value differs for different processors.

The comparator status value

Comp Status Values	F2837x/07	F28004x	F2838x
0	No comparator event occurred	No comparator event occurred	No comparator event occurred
1	Lower threshold event (LLT)	Lower threshold event (LLT) No HLTZ	Comparator event 1 (CEVT1). No HLTZ
2	Higher threshold event (HLT)	Higher threshold event (HLT) No HLTZ	Comparator event 2 (CEVT2). No HLTZ
3	NA	HLTZ. No HLT and no LLT	HLTZ. No CEVT1 and no CEVT2
4	NA	HLTZ and LLT	CEVT1 and HLTZ
5	NA	HLTZ and HLT	CEVT2 and HLTZ
-1	Modulator clock failure	Modulator clock failure	Modulator clock failure

Dependencies

To enable this port, select the Enable comparator filter output parameter.

CFLTX — Comparator filter

scalar

The secondary data filter output. CFLTX - x represents the filter channel.

This comparator filter is available only for specific processors.

Dependencies

To enable this port, select the Enable comparator filter output parameter.

Parameters

SDFM module — Indicates which register to use

1 (default) | 2

Select the SDFM register that should be configured to output the result.

Note

The F28004x processor has only one SDFM module.

Filter channel — Select filter module

Filter1 (default) | Filter2 | Filter3 | Filter4

Each filter channel consists of an input control unit, a data filter unit, and a comparator filter unit. Each of these filter modules can be independently configured. The SDFM module consists of four primary filters and four secondary filters.

Data representation — Source of internal DAC

16-bit (default) | 32-bit

The data filter output can be represented in either 32-bit or 16-bit format.

By default, the data filter output is represented in a 16-bit format. When the output is represented in a 16-bit format, required shifts are handled internally.

Sample time — Frequency at which data is read

0.1 (default)

Use this parameter to specify the time interval between samples. To inherit sample time from an upstream block, set this parameter to -1.

Enable comparator filter output — Enables comparator output ports

off (default) | on

Select this option to enable the comparator status (CFSTS) and comparator filter (CFLTX) output ports.

Version History

Introduced in R2020b