www.pudn.com > cc03-demo-spi-0_0_1.rar > spi_drv.c
/*C**************************************************************************
* NAME: spi_drv.c
*----------------------------------------------------------------------------
* Copyright (c) 2003 Atmel.
*----------------------------------------------------------------------------
* RELEASE: cc03-demo-spi-0_0_1
* REVISION: 1.1.1.1
*----------------------------------------------------------------------------
* PURPOSE:
* spi library low level functions (init, receive and send functions)
* and global variables declarations to use with user software application
*****************************************************************************/
/*_____ I N C L U D E S ____________________________________________________*/
#include "config.h"
#include "spi_drv.h"
/*_____ M A C R O S ________________________________________________________*/
/*_____ D E F I N I T I O N ________________________________________________*/
/*_____ D E C L A R A T I O N ______________________________________________*/
// Here are some global flags to use with spi library
// These global flags arec used to communicate with higher level functions ( user application )
volatile bit b_spi_error; // General pupose error flag
volatile bit b_spi_transmit_completed; // for interrupt transmition use ( set when completed )
volatile bit b_spi_busy; // set when spi interface is in use
// Here the globals variables to communicate with spi interrupt routine
volatile unsigned char *spi_string_ptr; // pointer to data buffer
volatile unsigned char spi_nb_data; // number of data
/*F**************************************************************************
* NAME: spi_master_init
*----------------------------------------------------------------------------
* PARAMS:
* cpol: bit CPOL value
* cpha: bit CPHA value
* ssdis: bit SSDIS value
* speed: Uchar spi speed ratio transmission Vs Fper
* return: none
*----------------------------------------------------------------------------
* PURPOSE:
* Initialize the spi module in master mode
*----------------------------------------------------------------------------
* EXAMPLE:
* spi_master_init(0,1,1,4); // init spi in mater mode with CPOL=0, CPHA=1,
* // SSDIS=1 and bitrate=Fper/4
*----------------------------------------------------------------------------
* NOTE:
*****************************************************************************/
void spi_master_init(bit cpol, bit cpha, bit ssdis,Uchar speed)
{
b_spi_busy=0;
b_spi_error=0;
b_spi_transmit_completed=0;
SPCON = 0;
SPCON |= MSK_SPCON_MSTR;
spi_set_speed(speed);
if (cpol) SPCON |= MSK_SPCON_CPOL;
if (cpha) SPCON |= MSK_SPCON_CPHA;
if (ssdis) SPCON |= MSK_SPCON_SSDIS;
SPCON |= MSK_SPCON_SPEN;
}
/*F**************************************************************************
* NAME: spi_slave_init
*----------------------------------------------------------------------------
* PARAMS:
* cpol: bit CPOL value
* cpha: bit CPHA value
* ssdis: bit SSDIS value
* return: none
*----------------------------------------------------------------------------
* PURPOSE:
* Initialize the spi module in slave mode
*----------------------------------------------------------------------------
* EXAMPLE:
* spi_master_init(0,1,1); // init spi in mater mode with CPOL=0, CPHA=1, SSDIS=1
*----------------------------------------------------------------------------
* NOTE:
*****************************************************************************/
void spi_slave_init(bit cpol, bit cpha, bit ssdis)
{
b_spi_busy=0;
b_spi_error=0;
b_spi_transmit_completed=0;
SPCON = 0;
if (cpol) SPCON |= MSK_SPCON_CPOL;
if (cpha) SPCON |= MSK_SPCON_CPHA;
if (ssdis) SPCON |= MSK_SPCON_SSDIS;
SPCON |= MSK_SPCON_SPEN;
}
/*F**************************************************************************
* NAME: spi_transmit_byte
*----------------------------------------------------------------------------
* PARAMS: tx_data: byte to send
* return: byte received
*----------------------------------------------------------------------------
* PURPOSE:
* Send and receive a byte with spi interface
*----------------------------------------------------------------------------
* NOTE:
* If a current spi transfert is on going, the function performs an active wait polling on spi event.
* This function can be used both in slave and master mode
*****************************************************************************/
unsigned char spi_transmit_byte(unsigned char tx_data)
{
unsigned char rx_data;
if ( b_spi_busy ) // If current transfert is on going
{
while(!Spif_set()); //Wait end of current transfert
rx_data=SPDAT;
}
SPDAT=tx_data;
b_spi_busy=1;
return rx_data;
}
/*F**************************************************************************
* NAME: spi_get_data
*----------------------------------------------------------------------------
* PARAMS: none
* return: byte received
*----------------------------------------------------------------------------
* PURPOSE:
* Return the content of the spi data register
*----------------------------------------------------------------------------
* NOTE:
* This function performs an active wait polling
*****************************************************************************/
unsigned char spi_get_data()
{
unsigned char to_return;
while(!Spif_set()); //Wait end of current transfert
to_return=SPDAT;
b_spi_busy=0; // Release spi ressouce
return to_return;
}
/*F**************************************************************************
* NAME: spi_put_data
*----------------------------------------------------------------------------
* PARAMS: to_transmit: data to send
* return: none
*----------------------------------------------------------------------------
* PURPOSE:
* Send a data byte to the spi interface
*----------------------------------------------------------------------------
* NOTE:
* This function should be use in spi slave mode to load spi data register
* with the next data to be transmited in slave mode
*****************************************************************************/
void spi_put_data( unsigned char to_transmit)
{
SPDAT=to_transmit;
}
/*F**************************************************************************
* NAME: spi_transmit_burst_polling
*----------------------------------------------------------------------------
* PARAMS: *ptr_buf: data to send
* nb_data: number of data to send
* return: none
*----------------------------------------------------------------------------
* PURPOSE:
* Transmit a data string throught the spi interface in polling mode
*----------------------------------------------------------------------------
* NOTE:
* This function performs an active wait polling
*****************************************************************************/
void spi_transmit_burst_polling( unsigned char *ptr_buf, unsigned char nb_data)
{
unsigned char received;
while (nb_data != 0)
{
while(Spte_set()) // Wait for transmit buffer free
{
SPDAT = *ptr_buf;
received = SPDAT;
*ptr_buf = received;
ptr_buf++;
nb_data--;
}
}
}
/*F**************************************************************************
* NAME: spi_set_speed
*----------------------------------------------------------------------------
* PARAMS: ratio: spi clock ratio/XTAL
* return: bit: status
*----------------------------------------------------------------------------
* PURPOSE:
* Configure the baud rate of the spi, set CR2, CR1, CR0
*----------------------------------------------------------------------------
* NOTE:
* This function is use only in spi master mode
*****************************************************************************/
bit spi_set_speed (unsigned char ratio)
{
switch ( ratio )
{
case 2:
SPCON |= SPI_RATIO_2;
return TRUE;
break;
case 4:
SPCON |= SPI_RATIO_4;
return TRUE;
break;
case 8:
SPCON |= SPI_RATIO_8;
return TRUE;
break;
case 16:
SPCON |= SPI_RATIO_16;
return TRUE;
break;
case 32:
SPCON |= SPI_RATIO_32;
return TRUE;
break;
case 64:
SPCON |= SPI_RATIO_64;
return TRUE;
break;
case 128:
SPCON |= SPI_RATIO_128;
return TRUE;
break;
default :
return FALSE;
break;
}
}
/*F**************************************************************************
* NAME: spi_transmit_burst_it
*----------------------------------------------------------------------------
* PARAMS:
* *string_ptr: the string which must be send
* data_nb: number of data to send
* return: bit
*----------------------------------------------------------------------------
* PURPOSE:
* Initialize an spi tranfert in interrupt mode
* Works in interrupt mode
* If a current transfert is on going, the function returns '0'
*----------------------------------------------------------------------------
* NOTE:
* This function can be used in slave or master mode
*****************************************************************************/
bit spi_transmit_burst_it (Uchar *string_ptr, Uchar data_nb)
{
if ( ~b_spi_busy )
{
b_spi_busy=1;
b_spi_transmit_completed=0;
b_spi_error=0;
spi_string_ptr = string_ptr;
spi_nb_data = data_nb;
SPDAT=*spi_string_ptr;
return 1;
}
else //current transfert on going
{
return 0;
}
}
/*F**************************************************************************
* NAME: spi_interrupt
*----------------------------------------------------------------------------
* PARAMS:
* *spi_string_ptr: the string which must be send
* spi_nb_data: number of data to send
* return: none
*----------------------------------------------------------------------------
* PURPOSE:
* spi - interruption program for serial transmission ( Master and Slave mode )
*----------------------------------------------------------------------------
* NOTE:
*****************************************************************************/
void spi_interrupt(void) interrupt IRQ_SPI
{
if(Spif_set())
{
*spi_string_ptr=SPDAT;
spi_nb_data--;
if (spi_nb_data!=0)
{
spi_string_ptr++;
SPDAT=*spi_string_ptr;
}
else
{
b_spi_busy=0;
b_spi_transmit_completed=1;
}
}
}