stm32f4/06-TouchScreen/xpt2046.c

126 lines
2.5 KiB
C
Raw Normal View History

#include "ch.h"
#include "hal.h"
#include "xpt2046.h"
static const SPIConfig _xpt2046_spi_config = {
NULL ,
XPT2046_NSS_PORT ,
XPT2046_NSS_PAD ,
SPI_CR1_BR_2 | SPI_CR1_BR_1 | SPI_CR1_BR_0
};
u16 _xpt2046_get_reading( u8 control )
{
u8 tData[3] = { control , 0 , 0 };
u8 rData[3] = { 0 , 0 , 0 };
#if SPI_USE_MUTUAL_EXCLUSION
spiAcquireBus( &( XPT2046_SPI_DRIVER ) );
#endif
palClearPad( XPT2046_NSS_PORT , XPT2046_NSS_PAD );
spiExchange( &( XPT2046_SPI_DRIVER ) , 3 , tData , rData );
palSetPad( XPT2046_NSS_PORT , XPT2046_NSS_PAD );
#if SPI_USE_MUTUAL_EXCLUSION
spiReleaseBus( &( XPT2046_SPI_DRIVER ) );
#endif
if ( ( control & 0x08 ) == 0 ) {
return ( rData[1] << 5 ) | ( rData[2] >> 3 );
}
return ( rData[1] << 4 ) | ( rData[2] >> 4 );
}
void xpt2046Init( void )
{
// Initialise SPI
spiStart( &( XPT2046_SPI_DRIVER ) , &_xpt2046_spi_config );
// NSS signal
palSetPadMode( XPT2046_NSS_PORT , XPT2046_NSS_PAD ,
PAL_MODE_OUTPUT_PUSHPULL );
palSetPad( XPT2046_NSS_PORT , XPT2046_NSS_PAD );
// Main SPI signals
palSetPadMode( XPT2046_CLK_PORT , XPT2046_CLK_PAD ,
PAL_MODE_ALTERNATE( 5 ) );
palSetPadMode( XPT2046_DIN_PORT , XPT2046_DIN_PAD ,
PAL_MODE_ALTERNATE( 5 ) );
palSetPadMode( XPT2046_DOUT_PORT , XPT2046_DOUT_PAD ,
PAL_MODE_ALTERNATE( 5 ) );
// PENIRQ signal
palSetPadMode( XPT2046_IRQ_PORT , XPT2046_IRQ_PAD , PAL_MODE_INPUT );
// Read a sample, leaving PENIRQ active
_xpt2046_get_reading( 0x90 );
}
int xpt2046GetCoordinates( int * pX , int * pY )
{
int i;
int allX[ 7 ] , allY[ 7 ];
_xpt2046_get_reading( 0xd1 );
_xpt2046_get_reading( 0x91 );
for ( i = 0 ; i < 7 ; i ++ ) {
allX[ i ] = _xpt2046_get_reading( 0xd1 );
allY[ i ] = _xpt2046_get_reading( 0x91 );
}
int j;
for ( i = 0 ; i < 4 ; i ++ ) {
for ( j = i ; j < 7 ; j ++ ) {
int temp = allX[ i ];
if ( temp > allX[ j ] ) {
allX[ i ] = allX[ j ];
allX[ j ] = temp;
}
temp = allY[ i ];
if ( temp > allY[ j ] ) {
allY[ i ] = allY[ j ];
allY[ j ] = temp;
}
}
}
_xpt2046_get_reading( 0x90 );
if ( palReadPad( XPT2046_IRQ_PORT , XPT2046_IRQ_PAD ) ) {
return 0;
}
*pX = allX[ 3 ];
*pY = allY[ 3 ];
return 1;
}
int xpt2046GetAverageCoordinates( int * pX , int * pY , int nSamples )
{
int nRead = 0;
int xAcc = 0 , yAcc = 0;
int x , y;
while ( nRead < nSamples ) {
if ( !xpt2046GetCoordinates( &x , &y ) ) {
break;
}
xAcc += x;
yAcc += y;
nRead ++;
}
if ( nRead == 0 ) {
return 0;
}
*pX = xAcc / nRead;
*pY = yAcc / nRead;
return 1;
}