hil_set_pwm_configuration :: Quanser C Functions

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hil_set_pwm_configuration

Sets the configuration, alignment and polarity of PWM outputs.

Description

The hil_set_pwm_configuration function sets the configuration that will be used for a PWM output, as well as their alignment and polarities. Currently supported configurations are:

Configuration	Description
PWM_UNIPOLAR_CONFIGURATION	The PWM output is unipolar, with a value of 0 or Vcc at any instant of time, where Vcc is the supply voltage (or I/O pin voltage).
PWM_BIPOLAR_CONFIGURATION	In the bipolar configuration, PWM outputs may take on -Vcc, 0 or +Vcc values. Only a select number of Quanser cards support this functionality. On the Quanser QPID and QPIDe cards, bipolar outputs appear on analog output pins instead of the PWM outputs.
PWM_PAIRED_CONFIGURATION	In the paired configuration, two PWM outputs are paired and are controlled by the first PWM output in the pair. The second output may have leading-edge and trailing-edge deadbands applied relative to the first signal.
PWM_COMPLEMENTARY_CONFIGURATION	The complementary configuration is like the paired configuration, except the second PWM output in the pair is an inverted version of the first PWM output in the pair. The second output may have leading-edge and trailing-edge deadbands applied relative to the first signal. This configuration is useful for driving H-bridges, for example.

The PWM alignment values may be:

Alignment	Description
PWM_LEADING_EDGE_ALIGNED	The leading edge of the pulse is aligned to the beginning of the PWM period.
PWM_TRAILING_EDGE_ALIGNED	The trailing edge of the pulse is aligned to the end of the PWM period.
PWM_CENTER_ALIGNED	The pulse is centered in the PWM period.

Valid PWM polarities are:

Polarity	Description
PWM_ACTIVE_LOW_POLARITY	The PWM output is active-low. In other words, the signal is inverted.
PWM_ACTIVE_HIGH_POLARITY	The PWM output is active-high.

The actual PWM output mode may not be changed until the PWM output is used in one of the following functions:

hil_task_start

Prototype

t_error
hil_set_pwm_configuration(t_card card, 
    const t_uint32 pwm_channels[], t_uint32 num_channels, 
    const t_pwm_configuration configurations[],
    const t_pwm_alignment alignments[], 
    const t_pwm_polarity polarities[]);

Parameters

t_card card

A handle to the board, as returned by hil_open .

const t_uint32 [] pwm_channels

An array containing the channel numbers of the PWM outputs whose configurations are being set.

Select a board type from the list for board-specific details: .

t_uint32 num_channels

The number of channels specified in the pwm_channels array.

const t_pwm_configuration [] configurations

An array containing the configurations of the PWM outputs. The array must contain num_channels elements. Each element in the configurations array corresponds to the same element in the pwm_channels array.

const t_pwm_alignment [] alignments

An array containing the alignments of the PWM outputs. The array must contain num_channels elements. Each element in the alignments array corresponds to the same element in the pwm_channels array.

const t_pwm_polarity [] polarities

An array containing the polarities of the PWM outputs. The array must contain num_channels elements. Each element in the polarities array corresponds to the same element in the pwm_channels array.

Return value

The return value is 0 if the PWM configurations are set successfully. Otherwise a negative error code is returned. Error codes are defined in quanser_errors.h. A suitable error message may be retrieved using msg_get_error_message .

Error codes

QERR_HIL_SET_PWM_CONFIGURATION_NOT_SUPPORTED

This function is not supported by the board-specific HIL driver for this board type.

QERR_INVALID_CARD_HANDLE

An invalid card handle was passed as an argument. Once a card has been closed using hil_close the card handle is invalid.

QERR_TOO_MANY_PWM_OUTPUT_CHANNELS

Too many PWM output channels were specified.

QERR_INVALID_PWM_OUTPUT_CHANNEL

One of the PWM output channels that was specified is not a valid channel number. Channel numbers range from 0 to one less than the number of channels.

QERR_INVALID_PWM_CONFIGURATION

One of the PWM configurations specified is not supported by this board.

QERR_INVALID_PWM_ALIGNMENT

One of the PWM alignments specified is not supported by this board.

QERR_INVALID_PWM_POLARITY

One of the PWM polarities specified is not supported by this board.

QERR_DRIVER_INCOMPATIBLE_WITH_BOARD_DLL

The board-specific HIL driver passed an invalid parameter to the operating system specific kernel-level driver for the board. The board-specific HIL driver is likely not compatible with the operating system specific kernel-level driver for the board. Make sure both are up-to-date and compatible versions.

QERR_INTERNAL_BUFFER_TOO_SMALL

The board-specific HIL driver used an internal buffer that was too small for the operating system specific kernel-level driver for the board. The board-specific HIL driver is likely not compatible with the operating system specific kernel-level driver for the board. Make sure both are up-to-date and compatible versions.

QERR_OUT_OF_REQUIRED_SYSTEM_RESOURCES

There are not enough system resources to perform the requested operation. Try rebooting, requesting fewer samples, or adding more memory to your machine.

Requirements

Include Files	Libraries
hil.h	hil.lib;quanser_runtime.lib;quanser_common.lib

Examples


/*
* Set the configuration of PWM channel 0 to be an independent output that is center-aligned with normal polarity.
* Set the configuration of PWM channel 1 to be an independent bipolar output that is edge-aligned with inverse polarity.
* Set the configuration of PWM channel 2 to be a complementary output that is center-aligned with normal polarity. For the QPID
* this setting will also determine the configuration of PWM channel 3 since it is paired with channel 2 as a complementary output.
*/

t_uint32 channels[] = { 0, 1, 2 };
t_pwm_configuration configurations[] = { PWM_UNIPOLAR_CONFIGURATION, PWM_BIPOLAR_CONFIGURATION, PWM_COMPLEMENTARY_CONFIGURATION };
t_pwm_alignment     alignments[]     = { PWM_CENTER_ALIGNED, PWM_EDGE_ALIGNED, PWM_CENTER_ALIGNED };
t_pwm_polarity      polarities[]     = { PWM_ACTIVE_HIGH_POLARITY, PWM_ACTIVE_LOW_POLARITY, PWM_ACTIVE_HIGH_POLARITY };
t_error result;

result = hil_set_pwm_configuration(card, channels, 3, configurations, alignments, polarities);

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