Sigma Delta Filter Module

Target Category: Delfino, F280x, Piccolo

Target Sub-Category: ADC

Description: The Sigma Delta Filter Module block is a four-channel digital filter for current measurement and resolver position decoding on newer TI devices, including F2837x and F28004x. This block is used in motor control applications.

Each input channel receives an independent delta-sigma modulator bit stream. The bit streams are processed by four individually-programmable digital decimation filters. The filter set includes a fast comparator filter for:

      Immediate digital threshold comparisons for over- and under-current monitoring

      Zeroes crossing detection

Additional information: Texas Instruments TI 28377D Technical Reference Manual.

Channel: Specifies the input channel.

Comparator Filter

Comparator High Val: Indicates the upper threshold for the signal. If you activate Enable High Val Interrupt and the signal crosses the upper threshold, corresponding bits will be set in the Interrupt Flag (SDIFLG) register.

Comparator Low Val: Indicates the lower threshold for the signal. If you activate Enable Low Val Interrupt and the signal crosses the lower threshold, corresponding bits will be set in the Interrupt Flag (SDIFLG) register.

Enable High Val Interrupt: Used in conjunction with Comparator High Val, it sets the corresponding bits in the Interrupt Flag (SDIFLG) register when the signal crosses the upper threshold.

Enable Low Value Interrupt: Used in conjunction with Comparator Low Val, it sets the corresponding bits in the Interrupt Flag (SDIFLG) register when the signal crosses the upper threshold.

Filter Structure: Indicates the filter structure to be used.

Oversampling Ratio: Lets you choose between 1 and 32. Higher values yield higher signal precision, but slower overall sampling rates. The maximum comparator value is displayed with the specified ratio.

Data Filter

Enable Data Filter: Enables the data filter to monitor the bit stream.

Enable Data Ready Acknowledge Interrupt Flag: Sets the Data Ready Interrupt flag.

Filter Structure: Indicates the filter structure to be used.

Max Filter Value: Displays the maximum and minimum data filter values. This is a read-only parameter.

Oversampling Ratio: Lets you choose between 1 and 256. Higher values yield higher signal precision, but slower overall sampling rates.

Sync with PWM11.CMPD: Synchronizes the oversampling ratio with the PWM.

Word Size: Selects the word size of the output.

Enable Modulator Clk Failure Interrupt Flag: Sets the Modulator Clock Failure  Interrupt flag.

Modulator Clk Mode: Lets you choose the speed of the modulator clock. If you are using Manchester encoded data, select No Clk.

SD1 C1 (clk): Chooses the pin that the clock comes in on.

SD1 D1(data): Chooses the pin that the data comes in on.

Unit: Specifies the unit number.