Persistence and Interrupts

SaveData.h

Header: core/src/Saves/SaveData.h

SaveData

Field	Type	Meaning
signature	uint8_t[4]	Save validity marker. Defaults to SAVE.

The struct also includes generated project save variables.

Globals

Name	Type	Meaning
save_data	SaveData	In-memory save data.

Functions

Function	Description
void save_save_data(void);	Writes the current save_data record to SRAM.

InterruptManager.h

Header: core/src/Interrupts/InterruptManager.h

Constants

Name	Value	Meaning
INTERRUPT_MANAGER_MAX_CALLBACKS	8U	Maximum VBlank, timer, or serial callbacks.
INTERRUPT_MANAGER_MAX_LCD_EVENTS	8U	Maximum LCD scanline events.
INTERRUPT_TIMER_4KHZ	TACF_4KHZ	Timer clock-select constant.
INTERRUPT_TIMER_16KHZ	TACF_16KHZ	Timer clock-select constant.
INTERRUPT_TIMER_65KHZ	TACF_65KHZ	Timer clock-select constant.
INTERRUPT_TIMER_262KHZ	TACF_262KHZ	Timer clock-select constant.

Types

Type	Meaning
InterruptCallback	void (*)(void)

LcdScanlineInterrupt

Field	Type	Meaning
ly	uint8_t	Scanline for the interrupt.
callback	InterruptCallback	Callback to run at that scanline.

Functions

Function	Description
uint8_t add_vblank_interrupt_callback(InterruptCallback callback) BANKED;	Adds a VBlank callback if it is non-null and not already registered.
uint8_t remove_vblank_interrupt_callback(InterruptCallback callback) BANKED;	Removes a VBlank callback.
void clear_vblank_interrupt_callbacks(void) BANKED;	Removes every VBlank callback.
void set_vblank_interrupt_callback(InterruptCallback callback) BANKED;	Replaces VBlank callbacks with one callback.
uint8_t add_serial_interrupt_callback(InterruptCallback callback) BANKED;	Adds a serial interrupt callback.
uint8_t remove_serial_interrupt_callback(InterruptCallback callback) BANKED;	Removes a serial interrupt callback.
void clear_serial_interrupt_callbacks(void) BANKED;	Clears serial callbacks.
void set_serial_interrupt_callback(InterruptCallback callback) BANKED;	Replaces serial callbacks with one callback.
uint8_t add_timer_interrupt_callback(InterruptCallback callback) BANKED;	Adds a timer interrupt callback.
uint8_t remove_timer_interrupt_callback(InterruptCallback callback) BANKED;	Removes a timer interrupt callback.
void clear_timer_interrupt_callbacks(void) BANKED;	Clears timer callbacks.
void set_timer_interrupt_callback(uint8_t clock_select, uint8_t modulo, InterruptCallback callback) BANKED;	Configures the timer and installs one callback.
void clear_lcd_scanline_interrupts(void) BANKED;	Clears all scheduled LCD scanline events.
uint8_t add_lcd_scanline_interrupt(uint8_t ly, InterruptCallback callback) BANKED;	Adds one LCD scanline event.
uint8_t remove_lcd_scanline_interrupt(uint8_t ly, InterruptCallback callback) BANKED;	Removes one LCD scanline event.
void clear_lcd_scanline_interrupts_for_callback(InterruptCallback callback) BANKED;	Removes every LCD scanline event using the given callback.

Behavior notes

• Duplicate callbacks are ignored and reported as success (you can add more than one callback to an interrupt but not the same one).
• LCD scanline events are ordered by ly and multiple callbacks can share the same scanline.

TimerInterrupt.h

Header: core/src/Interrupts/TimerInterrupt.h

Functions

Function	Description
void init_timer_interrupt(uint16_t frequency_hz, InterruptCallback callback) BANKED;	Starts a timer callback at the requested frequency. Passing 0 or NULL disables the timer.
void stop_timer_interrupt(void) BANKED;	Stops timer interrupts.

SerialLink.h

Header: core/src/Interrupts/SerialLink.h

Functions

Function	Description
void init_serial_link(uint8_t is_master) BANKED;	Initializes serial state and callbacks.
void shutdown_serial_link(void) BANKED;	Stops transfers and unregisters serial-related callbacks.
void send_serial_link_byte(uint8_t data) BANKED;	Starts a transfer when the link is idle.
uint8_t serial_link_ready(void) BANKED;	Returns nonzero when no transfer is in progress.
uint8_t serial_link_has_error(void) BANKED;	Returns nonzero when the last transfer timed out.
uint8_t get_serial_link_byte(void) BANKED;	Returns the most recently received byte.

Behavior notes

• Serial transfers time out after more than 10 VBlank ticks.
• Master mode sends with SC_REG = 0x81; slave mode uses 0x80.