1.3.17 Quadrature Decoder (PDEC)

The quadrature decoder (QDEC) mode is used to measure the position and speed of the motor. This provides below features:

• Angular and revolution counts

• Synchronous and asynchronous velocity measurements

• Direction change detection

• Interrupts/output events on:

  • Counter overflow/underflow

  • Velocity

  • Direction change

Using The Library

Quadrature encoder signals Phase A, Phase B and an optional index signal are connected to the PDEC peripheral. The PDEC peripheral processes these signals with an internal counter to get the angular position and revolution count.

For velocity measurement, velocity event output is connected to the TC module using the Event System.

Library Interface

Quadrature Decoder peripheral library provides the following interfaces:

Functions

Name	Description
PDECx_QDECInitialize	Initializes given instance of PDEC peripheral in quadrature mode
PDECx_QDECStart	Starts the given PDEC counter in quadrature mode
PDECx_QDECStop	Stops the given PDEC counter in quadrature mode
PDECx_QDECPositionGet	Reads the angular position from the quadrature encoder
PDECx_QDECRevolutionsGet	Reads the number of revolutions
PDECx_QDECAngleGet	Reads the angle
PDECx_QDECCallbackRegister	Registers the function to be called from interrupt
PDECx_QDECStatusGet	Identifies status of the quadrature interrupts
PDECx_HALLInitialize	Initializes given instance of PDEC peripheral in hall mode
PDECx_HALLStart	Starts the given PDEC counter in hall mode
PDECx_HALLStop	Stops the given PDEC counter in hall mode
PDECx_HALLPatternGet	Reads the hall pattern
PDECx_HALLPatternSet	Writes the hall pattern
PDECx_HALLTimeWindowSet	Writes the low and high window threshold for hall mode
PDECx_HALLCallbackRegister	Registers the function to be called from interrupt
PDECx_HALLStatusGet	Identifies status of the hall interrupts
PDECx_COUNTERInitialize	Initializes given instance of PDEC peripheral in counter mode
PDECx_COUNTERStart	Starts the given PDEC counter in counter mode
PDECx_COUNTERStop	Stops the given PDEC counter in counter mode
PDECx_COUNTERCompare0Set	Configures Compare 0 register value
PDECx_COUNTERCompare1Set	Configures Compare 0 register value
PDECx_COUNTERCompare0Get	Reads Compare 0 register value
PDECx_COUNTERCompare1Get	Reads Compare 1 register value
PDECx_COUNTERCallbackRegister	Registers the function to be called from interrupt
PDECx_COUNTERStatusGet	Identifies status of the counter mode interrupts

Data types and constants

Name	Type	Description
PDEC_QDEC_STATUS	Enum	Identifies Quadrature mode interrupt source mask
PDEC_HALL_STATUS	Enum	Identifies Hall mode interrupt source mask
PDEC_COUNTER_STATUS	Enum	Identifies counter mode interrupt source mask
PDEC_QDEC_CALLBACK	Typedef	Defines the function pointer data type and function signature for the pdec QDEC callback function
PDEC_HALL_CALLBACK	Typedef	Defines the function pointer data type and function signature for the pdec hall callback function
PDEC_COUNTER_CALLBACK	Typedef	Defines the function pointer data type and function signature for the pdec counter callback function
PDEC_QDEC_CALLBACK_OBJ	Struct	Callback structure
PDEC_HALL_CALLBACK_OBJ	Struct	Callback structure
PDEC_COUNTER_CALLBACK_OBJ	Struct	Callback structure