TMS320F28P659DK-Q1: EQEP latching with SOCA

Part Number: TMS320F28P659DK-Q1
Other Parts Discussed in Thread: SYSCONFIG

Hi Texas Community,

I currently have the PWM running and successfully generating SOCA and SOCB events, which are triggering the ADC conversions.

My next step is to latch the eQEP (Enhanced Quadrature Encoder Pulse) position with either the SOCA or SOCB signal to get the motor position synchronized with the ADC acquisition.

I've attempted the following configuration using the SysConfig tool:

1. Changed the STROBE source to "Strobe signal OR'd with ADCSOCA" (or ADCSOCB).

2. Tried to read the latched position using EQEP_getStrobePositionLatch(myEQEP0_BASE).

The issue is that this value is always zero.

Could you please provide insight into what I might be missing in the configuration?

The relevant code generated by the SysConfig tool is:

void myEQEP0_init(){
	//
	// Disable, clear all flags and interrupts
	//
	EQEP_disableInterrupt(myEQEP0_BASE,
		(EQEP_INT_GLOBAL     		|   
		EQEP_INT_POS_CNT_ERROR		|      
		EQEP_INT_PHASE_ERROR    	| 
		EQEP_INT_DIR_CHANGE    		| 
		EQEP_INT_WATCHDOG          	|   
		EQEP_INT_UNDERFLOW         	|
		EQEP_INT_OVERFLOW        	|
		EQEP_INT_POS_COMP_READY    	|	
		EQEP_INT_POS_COMP_MATCH   	|
		EQEP_INT_STROBE_EVNT_LATCH	| 
		EQEP_INT_INDEX_EVNT_LATCH 	|
		EQEP_INT_UNIT_TIME_OUT   	|
		EQEP_INT_QMA_ERROR));
	EQEP_clearInterruptStatus(myEQEP0_BASE,
		(EQEP_INT_GLOBAL     		|   
		EQEP_INT_POS_CNT_ERROR		|      
		EQEP_INT_PHASE_ERROR    	| 
		EQEP_INT_DIR_CHANGE    		| 
		EQEP_INT_WATCHDOG          	|   
		EQEP_INT_UNDERFLOW         	|
		EQEP_INT_OVERFLOW        	|
		EQEP_INT_POS_COMP_READY    	|	
		EQEP_INT_POS_COMP_MATCH   	|
		EQEP_INT_STROBE_EVNT_LATCH	| 
		EQEP_INT_INDEX_EVNT_LATCH 	|
		EQEP_INT_UNIT_TIME_OUT   	|
		EQEP_INT_QMA_ERROR));
	EQEP_SourceSelect source_myEQEP0 =
	{
		EQEP_SOURCE_DEVICE_PIN, 		// eQEPA source
		EQEP_SOURCE_DEVICE_PIN,		// eQEPB source
		EQEP_SOURCE_DEVICE_PIN,  	// eQEP Index source 
	};
	//
	// Selects the source for eQEPA/B/I signals
	//
	EQEP_selectSource(myEQEP0_BASE, source_myEQEP0);
	//
	// Set the strobe input source of the eQEP module.
	//
	EQEP_setStrobeSource(myEQEP0_BASE,EQEP_STROBE_OR_ADCSOCA);
	//
	// Sets the polarity of the eQEP module's input signals.
	//
	EQEP_setInputPolarity(myEQEP0_BASE,false,false,false,false);
	//
	// Configures eQEP module's quadrature decoder unit.
	//
	EQEP_setDecoderConfig(myEQEP0_BASE, (EQEP_CONFIG_QUADRATURE | EQEP_CONFIG_2X_RESOLUTION | EQEP_CONFIG_NO_SWAP | EQEP_CONFIG_IGATE_DISABLE));
	//
	// Set the emulation mode of the eQEP module.
	//
	EQEP_setEmulationMode(myEQEP0_BASE,EQEP_EMULATIONMODE_STOPIMMEDIATELY);
	//
	// Configures eQEP module position counter unit.
	//
	EQEP_setPositionCounterConfig(myEQEP0_BASE,EQEP_POSITION_RESET_IDX,1999U);
	//
	// Sets the current encoder position.
	//
	EQEP_setPosition(myEQEP0_BASE,0U);
	//
	// Disables the eQEP module unit timer.
	//
	EQEP_disableUnitTimer(myEQEP0_BASE);
	//
	// Disables the eQEP module watchdog timer.
	//
	EQEP_disableWatchdog(myEQEP0_BASE);
	//
	// Configures the quadrature modes in which the position count can be latched.
	//
	EQEP_setLatchMode(myEQEP0_BASE,(EQEP_LATCH_UNIT_TIME_OUT|EQEP_LATCH_RISING_STROBE|EQEP_LATCH_RISING_INDEX));
	//
	// Set the quadrature mode adapter (QMA) module mode.
	//
	EQEP_setQMAModuleMode(myEQEP0_BASE,EQEP_QMA_MODE_BYPASS);
	//
	// Disable Direction Change During Index
	//
	EQEP_disableDirectionChangeDuringIndex(myEQEP0_BASE);
	//
	// Enables individual eQEP module interrupt sources.
	//
	EQEP_enableInterrupt(myEQEP0_BASE,(EQEP_INT_INDEX_EVNT_LATCH));
	//
	// Configures the mode in which the position counter is initialized.
	//
	EQEP_setPositionInitMode(myEQEP0_BASE,(EQEP_INIT_FALLING_INDEX));
	//
	// Sets the software initialization of the encoder position counter.
	//
	EQEP_setSWPositionInit(myEQEP0_BASE,false);
	//
	// Sets the init value for the encoder position counter.
	//
	EQEP_setInitialPosition(myEQEP0_BASE,0U);
	//
	// Enables the eQEP module.
	//
	EQEP_enableModule(myEQEP0_BASE);
}

Thank you in advance,

Luciano.