Virtual Memory in RAM

The component manages a disk on a volatile memory (internal RAM).

This can be connected to a File System management or a USB Device Mass Storage Interface via the service Memory Control Access.

Functions
Ctrl_status	virtual_read_capacity (uint32_t *uint32_t_nb_sector)
	This function returns the address of the last valid sector. More...
bool	virtual_removal (void)
	This function informs about the memory type. More...
Ctrl_status	virtual_test_unit_ready (void)
	This function tests memory state, and starts memory initialization. More...
bool	virtual_unload (bool unload)
	This function unloads/loads the memory. More...
Ctrl_status	virtual_usb_read_10 (uint32_t addr, uint16_t nb_sector)
	This function transfers the memory data to the USB MSC interface. More...
static Ctrl_status	virtual_usb_trans (uint32_t addr, uint16_t nb_sector, bool b_read)
	This function transfers the data between memory and USB MSC interface. More...
Ctrl_status	virtual_usb_write_10 (uint32_t addr, uint16_t nb_sector)
	This function transfers the USB MSC data to the memory. More...
bool	virtual_wr_protect (void)
	This function returns the write-protected mode. More...

Variables
static bool	b_vmem_unloaded = false
static COMPILER_WORD_ALIGNED uint8_t	vmem_data [VMEM_NB_SECTOR *VMEM_SECTOR_SIZE]

Ctrl_status virtual_read_capacity

(

uint32_t *

uint32_t_nb_sector

)

This function returns the address of the last valid sector.

Parameters

uint32_t_nb_sector

Pointer to number of sectors (sector=512 bytes)

Returns

Ctrl_status It is ready -> CTRL_GOOD Memory unplug -> CTRL_NO_PRESENT Not initialized or changed -> CTRL_BUSY An error occurred -> CTRL_FAIL

References b_vmem_unloaded, CTRL_GOOD, CTRL_NO_PRESENT, and VMEM_NB_SECTOR.

bool virtual_removal

(

void

)

This function informs about the memory type.

Returns

true if the memory is removable

Ctrl_status virtual_test_unit_ready

(

void

)

This function tests memory state, and starts memory initialization.

Returns

Ctrl_status It is ready -> CTRL_GOOD Memory unplug -> CTRL_NO_PRESENT Not initialized or changed -> CTRL_BUSY An error occurred -> CTRL_FAIL

References b_vmem_unloaded, CTRL_GOOD, and CTRL_NO_PRESENT.

bool virtual_unload

(

bool

unload

)

This function unloads/loads the memory.

Returns

true if the memory is unloaded

References b_vmem_unloaded, and unload.

Ctrl_status virtual_usb_read_10	(	uint32_t	addr,
		uint16_t	nb_sector
	)

This function transfers the memory data to the USB MSC interface.

Parameters

addr	Sector address to start read
nb_sector	Number of sectors to transfer (sector=512 bytes)

Returns

Ctrl_status It is ready -> CTRL_GOOD Memory unplug -> CTRL_NO_PRESENT Not initialized or changed -> CTRL_BUSY An error occurred -> CTRL_FAIL

References virtual_usb_trans().

static Ctrl_status virtual_usb_trans ( uint32_t  addr, uint16_t  nb_sector, bool  b_read  )

static

This function transfers the data between memory and USB MSC interface.

Parameters

addr	Sector address to start read
nb_sector	Number of sectors to transfer (sector=512 bytes)
b_read	Memory to USB, if true

Returns

Ctrl_status It is ready -> CTRL_GOOD Memory unplug -> CTRL_NO_PRESENT Not initialized or changed -> CTRL_BUSY An error occurred -> CTRL_FAIL

References CTRL_FAIL, CTRL_GOOD, min, udi_msc_trans_block(), vmem_data, VMEM_NB_SECTOR, and VMEM_SECTOR_SIZE.

Referenced by virtual_usb_read_10(), and virtual_usb_write_10().

Ctrl_status virtual_usb_write_10	(	uint32_t	addr,
		uint16_t	nb_sector
	)

This function transfers the USB MSC data to the memory.

Parameters

addr	Sector address to start write
nb_sector	Number of sectors to transfer (sector=512 bytes)

Returns

Ctrl_status It is ready -> CTRL_GOOD Memory unplug -> CTRL_NO_PRESENT Not initialized or changed -> CTRL_BUSY An error occurred -> CTRL_FAIL

References virtual_usb_trans().

bool virtual_wr_protect

(

void

)

This function returns the write-protected mode.

Returns

true if the memory is protected

bool b_vmem_unloaded = false

static

Referenced by virtual_read_capacity(), virtual_test_unit_ready(), and virtual_unload().

COMPILER_WORD_ALIGNED uint8_t vmem_data[VMEM_NB_SECTOR *VMEM_SECTOR_SIZE]

static

Referenced by virtual_usb_trans().