nrf_axon_fir_24_24_24()

nrf_axon_result_e nrf_axon_fir_24_24_24	(	const int32_t *	in_ptr,
		const int32_t *	filter_ptr,
		int32_t *	out_ptr,
		uint16_t	input_length,
		uint16_t	filter_length,
		uint8_t	rounding_bits,
		nrf_axon_syncmode_blocking_e	block_mode,
		bool	keep_reservation )

#include <include/drivers/axon/nrf_axon_dsp_intrinsics.h>

"FIR" => "Finite Impulse Response" filter. Filter coefficients are MAC'd with the input in reverse order. ie, for filter length F, output x[n] = input[n-F]*filter[F-1] + input[n-F-1]*filter[F-2]+...input[n-1]*filter[0]. The filter output starts at outptr+ filter_length. out_ptr[0..filter_length-1] are written to but should be discarded.

Parameters

in_ptr	pointer to the input, 24bit integer sign-extended to 32bits.
filter_ptr	pointer to the filter coefficients, 24bit integer sign-extended to 32bits.
out_ptr	pointer to the output, int24 sign-extended to 32bits. 1st valid output starts at offset filter_length. Output can overlap/overwrite input.
input_length	length of the input (in elements). Must be a multiple of 4, maximum of 1024, and be at least 4 greater than filter_length
filter_length	length of the filter (in elements). Must be a at least 12, a multiple of 4 and the last coefficient must be 0. 0 pad as necessary to meet these requirements.
rounding_bits	number of bits to round the output by.
block_mode	recommnended to be set to NRF_AXON_SYNC_MODE_BLOCKING_POLLING.
keep_reservation	set to true if there are subsequent axon operations to execute immediately on completion. true prevents axon from be taken by another user and/or being powered off. Set to false if axon will not be used immediately after to free axon for other users and/or power down if idle.

Returns

kAxonResultSuccess on success or a negative error code (see nrf_axon_result_e)