unleashed-firmware/lib/digital_signal/digital_sequence.h
gornekich d92b0a82cc
NFC refactoring (#3050)
"A long time ago in a galaxy far, far away...." we started NFC subsystem refactoring.

Starring:

- @gornekich - NFC refactoring project lead, architect, senior developer
- @gsurkov - architect, senior developer
- @RebornedBrain - senior developer

Supporting roles:

- @skotopes, @DrZlo13, @hedger - general architecture advisors, code review
- @Astrrra, @doomwastaken, @Hellitron, @ImagineVagon333 - quality assurance

Special thanks:

@bettse, @pcunning, @nxv, @noproto, @AloneLiberty and everyone else who has been helping us all this time and contributing valuable knowledges, ideas and source code.
2023-10-24 12:08:09 +09:00

112 lines
3.9 KiB
C

/**
* @file digital_sequence.h
* @brief 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.
*/
#pragma once
#include <furi_hal_gpio.h>
#include <digital_signal/digital_signal.h>
#ifdef __cplusplus
extern "C" {
#endif
typedef struct DigitalSequence DigitalSequence;
/**
* @brief Allocate a DigitalSequence instance of a given size which will operate on a set GPIO pin.
*
* @param[in] size maximum number of signal indices contained in the instance.
* @param[in] gpio the GPIO pin used to generate the signal.
* @returns pointer to the allocated DigitalSequence instance.
*/
DigitalSequence* digital_sequence_alloc(uint32_t size, const GpioPin* gpio);
/**
* @brief Delete a previously allocated DigitalSequence instance.
*
* @param[in,out] sequence pointer to the instance to be deleted.
*/
void digital_sequence_free(DigitalSequence* sequence);
/**
* @brief 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.
*
* @param[in,out] sequence pointer to the instance to be modified.
* @param[in] signal_index index to register the signal under (must be less than 32).
* @param[in] signal pointer to the DigitalSignal instance to be registered.
*/
void digital_sequence_register_signal(
DigitalSequence* sequence,
uint8_t signal_index,
const DigitalSignal* signal);
/**
* @brief Append a signal index to a DigitalSequence instance.
*
* The signal under the index must be registered beforehand by calling digital_sequence_set_signal().
*
* @param[in,out] sequence pointer to the instance to be modified.
* @param[in] signal_index signal index to be appended to the sequence (must be less than 32).
*/
void digital_sequence_add_signal(DigitalSequence* sequence, uint8_t signal_index);
/**
* @brief 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.
*
* @param[in] sequence pointer to the sequence to be transmitted.
*/
void digital_sequence_transmit(DigitalSequence* sequence);
/**
* @brief 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.
*
* @param[in,out] sequence pointer to the instance to be cleared.
*/
void digital_sequence_clear(DigitalSequence* sequence);
#ifdef __cplusplus
}
#endif