Generic Character Device
[Device Driver API.]

Collaboration diagram for Generic Character Device:

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Detailed Description

Character Device Driver Template.

Extensively commented source code of a Nut/OS character device driver. It doesn't drive any specific device, but can be used as a template when adding new device drivers.

Data Structures
struct	DEVDCB
	Device driver's private data structure. More...
Defines
#define	GENDEV_SPORT   0x100
#define	GENDEV_DPORT   0x104
#define	GENDEV_SIGNAL   sig_INTERRUPT1
Functions
int	GenCharWrite_P (NUTFILE *fp, PGM_P buffer, int len)
	Write program data to the device.
long	GenCharSize (NUTFILE *fp)
	Retrieves the number of characters in input buffer.
Variables
NUTDEVICE	devGenChar
	Device information structure.

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Function Documentation

int GenCharWrite_P (  NUTFILE *  fp, PGM_P  buffer, int  len )

Write program data to the device. Similar to GenCharWrite() except that the data is located in program memory. This function is called by the low level output routines of the C runtime library, using the _NUTDEVICE::dev_write_P entry, which is available on Harvard architectures only. The function may block the calling thread. Parameters: fp  Pointer to a NUTFILE structure, obtained by a previous call to UsartOpen(). buffer  Pointer to the data in program space to be written. len  Number of bytes to write. Returns: The number of bytes written. With some devices this may be less than the number of bytes specified if a timeout occured. A return value of -1 indicates an error.

long GenCharSize (  NUTFILE *  fp  )

Retrieves the number of characters in input buffer. This function is called by the low level size routine of the C runtime library, using the _NUTDEVICE::dev_size entry. Parameters: fp  Pointer to a _NUTFILE structure, obtained by a previous call to UsartOpen(). Returns: The number of bytes currently stored in input buffer.

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Variable Documentation

NUTDEVICE devGenChar

Initial value: { 0, {'g', 'e', 'n', 'c', 'h', 'a', 'r', 0, 0}, IFTYP_CHAR, 0, 0, 0, &devdcb, GenCharInit, GenCharIOCtl, GenCharRead, GenCharWrite, GenCharWrite_P, GenCharOpen, GenCharClose, GenCharSize } Device information structure.

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