Generic Character Device

Character Device Driver Template. More...

Collaboration diagram for Generic Character Device:

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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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.

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Define Documentation

#define GENDEV_SPORT   0x100

#define GENDEV_DPORT   0x104

#define GENDEV_SIGNAL   sig_INTERRUPT1

Referenced by GenCharSize().

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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.

References DEVDCB::dcb_rcnt, _NUTDEVICE::dev_dcb, GENDEV_SIGNAL, _NUTFILE::nf_dev, NutIrqDisable(), NutIrqEnable(), and rc.

Here is the call graph for this function:

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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.