2.76 Quadrature Decoder (PDEC)
The quadrature decoder (QDEC) mode is used to measure the position and speed of the motor. This provides below features:
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Angular and revolution counts
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Synchronous and asynchronous velocity measurements
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Direction change detection
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Interrupts/output events on:
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Counter overflow/underflow
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Velocity
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Direction change
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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 |