SYSTEM

Device configuration, DMA, clocks, etc. More...

Detailed Description

Device configuration, DMA, clocks, etc.

Classes
class	daisy::System

Functions
void	dsy_dma_init (void)
void	dsy_dma_deinit (void)
void	dsy_dma_clear_cache_for_buffer (uint8_t *buffer, size_t size)
void	dsy_dma_invalidate_cache_for_buffer (uint8_t *buffer, size_t size)

Function Documentation

dsy_dma_clear_cache_for_buffer()

void dsy_dma_clear_cache_for_buffer	(	uint8_t *	buffer,
		size_t	size
	)

DMA transfers require the buffers to be excluded from the cache because the DMA reads / writes directly to the SRAM whereas the processor itself accesses the cache. Otherwise the DMA will access whatever is in the SRAM at the time which may not be in sync with the data in the cache - resulting in wrong data transmitted / received. You can place buffers in the D2 memory domain, in a section that has the cache disabled like this: uint8_t DMA_BUFFER_MEM_SECTION my_buffer[100]; If this is not possible for some reason, call this function to clear the cache (write cache contents to SRAM if required) before starting to transmit data via the DMA.

dsy_dma_deinit()

void dsy_dma_deinit

(

void

)

Deinitializes the DMA (specifically for the modules used within the library)

dsy_dma_init()

void dsy_dma_init

(

void

)

Initializes the Direct Memory Access Peripheral used by many internal elements of libdaisy. Initializes the DMA (specifically for the modules used within the library)

dsy_dma_invalidate_cache_for_buffer()

void dsy_dma_invalidate_cache_for_buffer	(	uint8_t *	buffer,
		size_t	size
	)

DMA transfers require the buffers to be excluded from the cache because the DMA reads / writes directly to the SRAM whereas the processor itself accesses the cache. Otherwise the DMA will access whatever is in the SRAM at the time which may not be in sync with the data in the cache - resulting in wrong data transmitted / received. You can place buffers in the D2 memory domain, in a section that has the cache disabled like this: uint8_t DMA_BUFFER_MEM_SECTION my_buffer[100]; If this is not possible for some reason, call this function to invalidate the cache (read SRAM contents to cache if required) after reading data from peripherals via the DMA.