Table of Contents
hil_set_clock_frequency
Sets the frequencies of the given hardware clocks.
Description
The hil_set_clock_frequency function sets the frequencies of the given hardware clocks. This function is typically used in conjunction with hil_set_card_specific_options to program a counter to drive some other function of the card, such as A/D conversions.
Prototype
t_error hil_set_clock_frequency(t_card card, const t_clock clocks[], t_uint32 num_clocks, const t_double clock_frequencies[]);
Parameters
t_card card
A handle to the board, as returned by hil_open.
const t_clock * clocks
An array containing the clocks whose frequencies will be changed. System clocks do not support different frequencies so only hardware clocks, such as HARDWARE_CLOCK_0, should be specified.
Select a board type from the list for board-specific details: .
t_uint32 num_clocks
The number of clocks specified in the clocks and clock_frequencies arrays.
const t_double * clock_frequencies
An array of frequencies, in Hertz, to which to set the clocks. Each element in the clock_frequencies array corresponds to the same element in the clocks array. Hence, there must be as many elements in the clock_frequencies array as there are clocks. If a frequency of zero is specified for any element then that clock is disabled.
Return value
The return value is 0 if the clock frequencies 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_CLOCK_FREQUENCY_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_CLOCKS
Too many clocks were specified.
QERR_CLOCK_NOT_SUPPORTED
One of the clocks that was specified is not a valid clock. Clock numbers range from 0 to one less than the number of hardware clocks.
QERR_CLOCK_FREQUENCY_TOO_LOW
One of the clock frequencies that was specified was too low for the corresponding clock. Clock frequencies of zero are a special case and do not generate this error.
QERR_CLOCK_FREQUENCY_TOO_HIGH
One of the clock frequencies that was specified was too high for the corresponding clock.
QERR_HARDWARE_CLOCK_IN_USE
One of the specified clocks is already in use for another operation and the board-specific HIL driver for this board does not permit sharing of the hardware clock.
Requirements
Include Files |
Libraries |
---|---|
hil.h |
hil.lib;quanser_runtime.lib;quanser_common.lib |
Examples
/* Set HARDWARE_CLOCK_0 to 1 MHz. */
t_uint32 clocks[] = { HARDWARE_CLOCK_0 };
t_int32 frequencies[] = { 1e6 };
t_error result = hil_set_clock_frequency(board, clocks, ARRAY_LENGTH(clocks), frequencies);
See Also
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