F2807x/F2837xD/F2837xS/F28004x/F2838x CMPSS

Compare two input voltages on comparator pins

• 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 / F2838x/ C28x

• 

Description

The Comparator Subsystem consists of two modules, Comparator High (COMPH) and Comparator Low (COMPH). Each module generates a high digital output when the voltage on the first input pin (positive input) is greater than the voltage on the second input pin (negative input). And each module generates a low digital output when the voltage on the first input pin (positive input) is less than the voltage on the second input pin (negative input).

The second input pin can either be the external pin or the DAC module.

Ports

Input

DAC — DAC module

scalar

12-bit DAC reference value is used for the second input pin of the comparator.

The DAC range is between 0 to 4095. Any value outside the range is saturated.

Dependencies

The DAC port appears only when parameter:

• Second input is set to Internal DAC

• DAC source select is set to DAC module

• Specify DAC/RAMP parameter(s) Via is set to Input port

REF — Ramp reference value

scalar

Ramp reference value used by the ramp generator to create a ramp reference voltage for the second input pin of the comparator.

The REF value should be in the range 0 to 65535. Any value outside the range is saturated.

Dependencies

The REF port appears only when parameter:

• Second input is set to Internal DAC

• DAC source select is set to RAMP module

• Specify DAC/RAMP parameter(s) Via is set to Input port

• This port is available only for the COMPH module.

DEC — RAMP decrement value

scalar

Ramp decrement value used by the ramp generator to create a ramp reference voltage for the second input pin of the comparator.

DEC range is between 0 to 65535. Any value outside the range is saturated.

Dependencies

The DEC port appears only when parameter:

• Second input is set to Internal DAC

• DAC source select is set to RAMP module

• Specify DAC/RAMP parameter(s) Via is set to Input port

• This port is available only for the COMPH module.

DLY — RAMP delay value

scalar

Ramp delay value used by the ramp generator to create a ramp reference voltage for the second input pin of the comparator.

DLY range is between 0 to 8192. Any value outside the range is saturated.

Dependencies

The DLY port appears only when parameter:

• Second input is set to Internal DAC

• DAC source select is set to RAMP module

• Specify DAC/RAMP parameter(s) Via is set to Input port

• This port is available only for the COMPH module.

LCLR — Latch clear

scalar

Signal to clear the comparator latched output. Any value greater than 0 will clear the latch output.

Dependencies

The latch clear port appears only when Enable latch clear parameter is selected.

Output

STS — Comparator status output

scalar

The comparator module outputs 1, if the voltage on the first input pin is greater than the second input pin. Otherwise, it outputs 0.

LTH — Comparator latch

scalar

The comparator latch output is the tripped state of the CMPSS comparator after it is digitized and qualified by a digital filter.

The latched value can either be cleared by the software or PWMSYNC.

Dependencies

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

Parameters

Comparator module — Indicates which module to use

CMPSS1_COMPH (default) | CMPSSx_COMPL | CMPSSx_COMPH | where x ranges from 1 to 8

Select which comparator module should be configured to output the comparison result.

Note

Number of modules available will vary for different processors.

Second input — Source of second input pin

External pin (default) | Internal DAC

The voltage source of second input pin (negative input pin), specified as either External pin or Internal DAC.

DAC source select — Source of internal DAC

DAC module (default) | RAMP module

Select source of the internal DAC to generate voltage for the negative input pin, specified as either DAC module or RAMP module.

Dependencies

This parameter is available only for the COMPH module.

Specify DAC/RAMP parameter(s) via — Configure source DAC/RAMP value source

Dialog (default) | Input port

Select if the DAC or RAMP values are to be specified via the input port or from the dialog.

When you select input port, the block generates input ports for the comparator module.

When you set DAC source select parameter to DAC module, the block generates DAC port and when DAC source select is set to RAMP module it generates REF, DEC, and DLY port.

Parameter dependency

This parameter is available only for the COMPH module.

DAC value (DACH) — Specify DAC value

0 (default)

Specify the DAC value for internal DAC to generate the voltage on the negative input.

Dependencies

The DAC port appears only when parameter:

• Second input is set to Internal DAC

• DAC source select is set to DAC module

• Specify DAC/RAMP parameter(s) Via is set to Input port

RAMP reference value — Specify RAMP reference value

0 (default)

The RAMP reference value is in the range 0 to 65535. Any value outside the range is saturated.

The RAMP generator starts to decrement from the reference value.

Dependencies

The REF port appears only when parameter:

• Second input is set to Internal DAC

• DAC source select is set to RAMP module

• Specify DAC/RAMP parameter(s) Via is set to Input port

• This port is available only for the COMPH module.

RAMP decrement value — Specify RAMP decrement value

0 (default)

The RAMP decrement value is in range 0 to 65535. Any value outside the range is saturated.

The RAMP generator decrements the RAMP reference value in steps of decrement value.

Dependencies

The DEC port appears only when parameter:

• Second input is set to Internal DAC

• DAC source select is set to RAMP module

• Specify DAC/RAMP parameter(s) Via is set to Input port

• This port is available only for the COMPH module.

RAMP delay value — Specify RAMP delay value

0 (default)

The RAMP delay value is in range 0 to 8192. Any value outside the range is saturated.

The RAMP generator waits for the delay value before it starts to decrement the RAMP reference value in steps of RAMP decrement value.

Dependencies

The DLY port appears only when parameter:

• Second input is set to Internal DAC

• DAC source select is set to RAMP module

• Specify DAC/RAMP parameter(s) via is set to Input port

• This port is available only for the COMPH module.

Enable latch output — Comparator latch output

off (default) | on

The latched value of the digital filter output of the comparator.

Select this parameter to enable the LTH port.

Enable latch clear — Clear comparator latch value

off (default) | on

Latch clear signals to clear the comparator latch status signal. Any value greater than 0 will clear the latch signal.

Select this parameter to enable the LCLR port.

Sample time — Frequency at which data is read from comparator

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.

Introduced in R2020a