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