digital_sequence.h File Reference

Fast and precise digital signal generation library. More...

#include <furi_hal_gpio.h>
#include <digital_signal/digital_signal.h>

Go to the source code of this file.

Typedefs
typedef struct DigitalSequence	DigitalSequence

Functions
DigitalSequence *	digital_sequence_alloc (uint32_t size, const GpioPin *gpio)
	Allocate a DigitalSequence instance of a given size which will operate on a set GPIO pin.
void	digital_sequence_free (DigitalSequence *sequence)
	Delete a previously allocated DigitalSequence instance.
void	digital_sequence_register_signal (DigitalSequence *sequence, uint8_t signal_index, const DigitalSignal *signal)
	Register a signal within a DigitalSequence instance by its index.
void	digital_sequence_add_signal (DigitalSequence *sequence, uint8_t signal_index)
	Append a signal index to a DigitalSequence instance.
void	digital_sequence_transmit (DigitalSequence *sequence)
	Transmit the sequence contained in the DigitalSequence instance.
void	digital_sequence_clear (DigitalSequence *sequence)
	Clear the signal sequence in a DigitalSequence instance.

Detailed Description

Fast and precise digital signal generation library.

Each sequence is represented by one or more (up to 32) registered signals, which are addressed by their indices, and a list of signal indices to be transmitted.

The registered signals must be set up prior to actually defining the sequence.

Example: A sequence containing 4 registered signals and n indices to transmit.

Signal	Index
SOF	0
EOF	1
Zero	2
One	3

Signal index | 0 | 3 | 2 | 2 | ... |   3   |   1   |
               0   1   2   3   ...   n - 2   n - 1

The above sequence starts by transmitting the signal with index 0, which is SOF in this case, then it proceeds with indices 3, 2, 2, which are One, Zero, Zero and after n - 2 signals, it will conclude with indices 3 and 1 which are One and EOF respectively.

This way, only the order in which the signals are sent is stored, while the signals themselves are not duplicated.

Function Documentation

digital_sequence_add_signal()

void digital_sequence_add_signal	(	DigitalSequence *	sequence,
		uint8_t	signal_index )

Append a signal index to a DigitalSequence instance.

The signal under the index must be registered beforehand by calling digital_sequence_set_signal().

Parameters

[in,out]	sequence	pointer to the instance to be modified.
[in]	signal_index	signal index to be appended to the sequence (must be less than 32).

digital_sequence_alloc()

DigitalSequence * digital_sequence_alloc	(	uint32_t	size,
		const GpioPin *	gpio )

Allocate a DigitalSequence instance of a given size which will operate on a set GPIO pin.

Parameters

[in]	size	maximum number of signal indices contained in the instance.
[in]	gpio	the GPIO pin used to generate the signal.

Returns

pointer to the allocated DigitalSequence instance.

digital_sequence_clear()

void digital_sequence_clear

(

DigitalSequence *

sequence

)

Clear the signal sequence in a DigitalSequence instance.

Calling this function does not un-register the registered signals, so it is safe to call digital_sequence_add_signal() right afterwards.

Parameters

[in,out]

sequence

pointer to the instance to be cleared.

digital_sequence_free()

void digital_sequence_free

(

DigitalSequence *

sequence

)

Delete a previously allocated DigitalSequence instance.

Parameters

[in,out]

sequence

pointer to the instance to be deleted.

digital_sequence_register_signal()

void digital_sequence_register_signal	(	DigitalSequence *	sequence,
		uint8_t	signal_index,
		const DigitalSignal *	signal )

Register a signal within a DigitalSequence instance by its index.

This function must be called for each signal to be used in the sequence. The DigitalSequence instance does not own the signals, therefore, their lifetime must be no less than the instance's.

The user is responsible for creation and deletion of DigitalSignal instances and also for keeping track of their respective indices.

Parameters

[in,out]	sequence	pointer to the instance to be modified.
[in]	signal_index	index to register the signal under (must be less than 32).
[in]	signal	pointer to the DigitalSignal instance to be registered.

digital_sequence_transmit()

void digital_sequence_transmit

(

DigitalSequence *

sequence

)

Transmit the sequence contained in the DigitalSequence instance.

Must contain at least one registered signal and one signal index.

NOTE: The current implementation will properly initialise the GPIO provided during construction, but it is the caller's responsibility to reconfigure it back before reusing for other purposes. This is due to performance reasons.

Parameters

[in]

sequence

pointer to the sequence to be transmitted.

Special case: during the last period of the last signal, hold the output level indefinitely.

See also

digital_signal.h

Setting reload_value_carry to a non-zero value will prevent the respective period from being added to the DMA ring buffer.