www.pudn.com > 8255_code_lib.rar > DIOFNC06.C

/*- 
 *  ---------------------------------------------------------------------- 
 *  File        :   DIOFNC06.C 
 *  Creator     :   Blake Miller 
 *  Version     :   01.01.00        February 1991 
 *  Language    :   Microsoft C     Version 5.1 
 *  Purpose     :   Intel 8255 Compatible Digital IO Functions 
 *                  8255 Get Byte Function 
 *  ---------------------------------------------------------------------- 
 *  Revision History: 
 *  022891 BVM  :   Change int to short. 
 *  070490 BVM  :   Creation 
 *  ---------------------------------------------------------------------- 
 */ 
 
#define     DIOFNC06_C_DEFINED  1 
#include    "DIOLIB.H" 
#undef      DIOFNC06_C_DEFINED 
 
void dio_get_byte (DIODAT *data, short port, unsigned char *p_dat); 
 
/*- DIO : Byte Get ---------------------------** 
 *  Read one of the bytes in the 8255. 
 *  The port number should be 0 - 2 as follows: 
 *  Use the defines (DIOLIB.H): 
 *  DIO_PORTA = 0 = Port A 
 *  DIO_PORTB = 1 = Port B 
 *  DIO_PORTC = 2 = Port C 
 *  Reads the 8255 and returns data in variable as well as 
 *  loading port data area. 
 *  Passed: 
 *      pointer :   DIODAT 
 *      short   :   port number 
 *      pointer :   unsigned char : returned port data 
 *  Returns: 
 *      nothing 
 *      Loads stat with appropriate error code. 
 *      Loads p_dat with returned data. 
 */ 
void dio_get_byte (DIODAT *data, short port, unsigned char *p_dat) 
	{ 
	unsigned char ival; 
 
	/*  Make sure the port requested is valid. 
	 *  Three ports. 
	 */ 
	if ( (port < DIO_PORTA) || (port > DIO_PORTC) ){ 
		data->stat = DIO_ST_BP; 
		return; 
		} 
 
	/*  Input the data. 
	 *  Save the input data. 
	 *  Store to return buffer. 
	 *  Indicate all is okay. 
	 */ 
	dio_bget ( data->base + port, &ival ); 
	data->pdat[port] = ival; 
	data->stat = DIO_ST_OK; 
	*p_dat = ival; 
	} 
 
/*- 
 *  ---------------------------------------------------------------------- 
 *  END DIOFNC06.C Source File 
 *  ---------------------------------------------------------------------- 
 */