qep.c File Reference

Support for eQEP for the BeagleBone Black. More...

#include <libcpu/am335x.h>
#include <stdio.h>
#include <stdlib.h>
#include <bsp/gpio.h>
#include <bsp/bbb-gpio.h>
#include <bsp.h>
#include <bsp/pwmss.h>
#include <bsp/qep.h>
#include <bsp/beagleboneblack.h>

Functions
rtems_status_code	beagle_qep_init (BBB_PWMSS pwmss_id)
	Initialises the eQEP module of the specified PWMSS unit. This configures the clocks, sets up the interrupt handler and unit timer, The module is configured in Quadrature decode mode using absolute position by default.
rtems_status_code	beagle_qep_enable (BBB_PWMSS pwmss_id)
	Enables the eQEP module of the specified PWMSS unit.
rtems_status_code	beagle_qep_disable (BBB_PWMSS pwmss_id)
	Disables the eQEP module of the specified PWMSS unit.
rtems_status_code	beagle_qep_pinmux_setup (bbb_qep_pin pin_no, BBB_PWMSS pwmss_id, bool pullup_enable)
	Configures a given pin for use with the eQEP function of the supplied PWMSS module.
int32_t	beagle_qep_get_position (BBB_PWMSS pwmss_id)
	Returns the current position value of the eQEP function for the specified PWMSS module.
rtems_status_code	beagle_qep_set_position (BBB_PWMSS pwmss_id, uint32_t position)
	Sets the initial position value of the eQEP function for the specified PWMSS module.
rtems_status_code	beagle_qep_set_count_mode (BBB_PWMSS pwmss_id, BBB_QEP_COUNT_MODE mode)
	Sets the count mode for the eQEP module.
BBB_QEP_COUNT_MODE	beagle_qep_get_count_mode (BBB_PWMSS pwmss_id)
	Gets the currently configured count mode for the eQEP module.
rtems_status_code	beagle_qep_set_quadrature_mode (BBB_PWMSS pwmss_id, BBB_QEP_QUADRATURE_MODE mode)
	Sets the quadrature mode to either absolute or relative.
BBB_QEP_QUADRATURE_MODE	beagle_qep_get_quadrature_mode (BBB_PWMSS pwmss_id)
	Returns the currently configured quadrature mode - either absolute, or relative.
uint32_t	beagle_eqep_get_timer_period (BBB_PWMSS pwmss_id)
	Returns the the currently configured unit timer period.
rtems_status_code	beagle_eqep_set_timer_period (BBB_PWMSS pwmss_id, uint64_t period, bbb_eqep_timer_callback timer_callback, void *user)
	Sets the unit timer period for the eQEP module. 0 = off, greater than zero sets the period.

Detailed Description

Support for eQEP for the BeagleBone Black.

Function Documentation

beagle_eqep_get_timer_period()

uint32_t beagle_eqep_get_timer_period

(

BBB_PWMSS

pwmss_id

)

Returns the the currently configured unit timer period.

Parameters

pwmss_id

Identifies which PWMSS module to get the eQEP timer value for

Returns

uint32_t The current unit timer value in nanoseconds

beagle_eqep_set_timer_period()

rtems_status_code beagle_eqep_set_timer_period	(	BBB_PWMSS	pwmss_id,
		uint64_t	period,
		bbb_eqep_timer_callback	timer_callback,
		void *	user
	)

Sets the unit timer period for the eQEP module. 0 = off, greater than zero sets the period.

Parameters

pwmss_id	Identifies which PWMSS module to set the eQEP unit timer for.
period	The value in nanoseconds to set the unit timer period to.
timer_callback	This is the user provided callback function that will be called by the interrupt event handler on expiry of the unit timer. The user can provide NULL if they don't require a call back.
user	This is a pointer to a user provided data structure that will be handed back as an argument to the timer callback. The driver does not touch this value.

Returns

RTEMS_SUCCESSFUL if ok, RTEMS_INVALID_ID if an invalid pwmss_id is supplied.

beagle_qep_disable()

rtems_status_code beagle_qep_disable

(

BBB_PWMSS

pwmss_id

)

Disables the eQEP module of the specified PWMSS unit.

Parameters

pwmss_id

The PWMSS module which will have the eQEP function disabled.

Returns

RTEMS_SUCCESSFUL if ok, RTEMS_INVALID_ID if an invalid pwmss_id is supplied.

beagle_qep_enable()

rtems_status_code beagle_qep_enable

(

BBB_PWMSS

pwmss_id

)

Enables the eQEP module of the specified PWMSS unit.

Parameters

pwmss_id

The PWMSS module which will have the eQEP function enabled.

Returns

RTEMS_SUCCESSFUL if ok, RTEMS_INVALID_ID if an invalid pwmss_id is supplied.

beagle_qep_get_count_mode()

BBB_QEP_COUNT_MODE beagle_qep_get_count_mode

(

BBB_PWMSS

pwmss_id

)

Gets the currently configured count mode for the eQEP module.

Parameters

pwmss_id

Identifies which PWMSS module to set the eQEP count mode for.

Returns

An enum value representing the current count mode.

beagle_qep_get_position()

int32_t beagle_qep_get_position

(

BBB_PWMSS

pwmss_id

)

Returns the current position value of the eQEP function for the specified PWMSS module.

Parameters

pwmss_id

Identifies which PWMSS module to return the eQEP position for

Returns

int32_t The current position value.

beagle_qep_get_quadrature_mode()

BBB_QEP_QUADRATURE_MODE beagle_qep_get_quadrature_mode

(

BBB_PWMSS

pwmss_id

)

Returns the currently configured quadrature mode - either absolute, or relative.

Parameters

pwmss_id

Identifies which PWMSS module to get the eQEP quadrature mode for.

Returns

BBB_QEP_QUADRATURE_MODE The currently configured quadrature mode.

beagle_qep_init()

rtems_status_code beagle_qep_init

(

BBB_PWMSS

pwmss_id

)

Initialises the eQEP module of the specified PWMSS unit. This configures the clocks, sets up the interrupt handler and unit timer, The module is configured in Quadrature decode mode using absolute position by default.

Parameters

pwmss_id

The PWMSS module to configure the eQEP for.

Returns

RTEMS_SUCCESSFUL if ok, RTEMS_INVALID_ID if an invalid pwmss_id is supplied.

beagle_qep_pinmux_setup()

rtems_status_code beagle_qep_pinmux_setup	(	bbb_qep_pin	pin_no,
		BBB_PWMSS	pwmss_id,
		bool	pullup_enable
	)

Configures a given pin for use with the eQEP function of the supplied PWMSS module.

Parameters

pin_no	The P9 or P8 header pin to be configured for the eQEP function.
pwmss_id	The PWMSS module which will have the eQEP function enabled.
pullup_enable	If true then the internal pull up resistor on the specified pin will be enabled, if false the pull down will be enabled.

Returns

RTEMS_SUCCESSFUL if ok, RTEMS_INVALID_ID if an invalid pwmss_id is supplied.

beagle_qep_set_count_mode()

rtems_status_code beagle_qep_set_count_mode	(	BBB_PWMSS	pwmss_id,
		BBB_QEP_COUNT_MODE	mode
	)

Sets the count mode for the eQEP module.

Parameters

pwmss_id	Identifies which PWMSS module to set the eQEP count mode for.
mode	One of the above modes to configure the eQEP module for.

Returns

RTEMS_SUCCESSFUL if ok, RTEMS_INVALID_ID if an invalid pwmss_id is supplied.

beagle_qep_set_position()

rtems_status_code beagle_qep_set_position	(	BBB_PWMSS	pwmss_id,
		uint32_t	position
	)

Sets the initial position value of the eQEP function for the specified PWMSS module.

Parameters

pwmss_id	Identifies which PWMSS module to set the eQEP position for
position	The value to initialise the position register with.

Returns

RTEMS_SUCCESSFUL if ok, RTEMS_INVALID_ID if an invalid pwmss_id is supplied.

beagle_qep_set_quadrature_mode()

rtems_status_code beagle_qep_set_quadrature_mode	(	BBB_PWMSS	pwmss_id,
		BBB_QEP_QUADRATURE_MODE	mode
	)

Sets the quadrature mode to either absolute or relative.

Parameters

pwmss_id	Identifies which PWMSS module to set the eQEP quadrature mode for.
mode	BBB_QEP_QUADRATURE_MODE Set the mode of the eQEP to either absolute or relative.

Returns

RTEMS_SUCCESSFUL if ok, RTEMS_INVALID_ID if an invalid pwmss_id is supplied.