source: umon/ports/csb740/ads7846.c @ ddf6706

//==========================================================================
//
//      ads7846.c
//
// Author(s):   Michael Kelly - Cogent Computer Systems, Inc.
// Date:        03/06/03
// Description: ADS7846 Interface routines for CSB740
//                              Modified from MC9328mxl version to use SPI1 
//
//==========================================================================

#include "config.h"
#include "cpuio.h"
#include "genlib.h"
#include "stddefs.h"
#include "omap3530.h"
#include "cpu_gpio.h"
#include "ads7846.h"
#include "cli.h"
#include "umongpio.h"

//--------------------------------------------------------------------------
// function prototypes
//
int ads_init(void);
int ads_rd(uchar ads_ctl);

extern void udelay(int delay);

//--------------------------------------------------------------------------
// ads_init()
//
// This routine sets up the OMAP3530 SPI3 port in Microwire mode
// (8 bit control, 16 bit data, 24 bit total).  It also turns on
// the ADS7843 pen interrupt via a dummy read.  Note that we assume
// that PERCLK2 is 12Mhz (HCLK/4). We are using CS0 on SPI3.  
//
int ads_init()
{
        volatile uchar temp;


        SPI3_REG(SPI_CH0_CTRL) = 0x00;                          // Disable SPI3 Channel 0

        SPI3_REG(SPI_CH0_CONF) = SPI_CH_CONF_CLKG
                                           | SPI_CH_CONF_DPE0   // no transmission on SPI3_MISO
                                           | SPI_CH_CONF_WL(7)          // 8-bit data mode
                                           | SPI_CH_CONF_EPOL           // CS is active low
//                                         | SPI_CH_CONF_SB_POL         // 
//                                         | SPI_CH_CONF_SBE            // 
                                           | SPI_CH_CONF_CLKD(9);       // divide by 512 = 93Khz
//                                         | SPI_CH_CONF_PHA;           // Data is latched on even numbered edges
//                                         | SPI_CH_CONF_POL;           // SPI clock is active low

        SPI3_REG(SPI_MODULCTRL) = 0x0;                          // Functional mode, Master, and auto CS generation

        SPI3_REG(SPI_CH0_CTRL) = 0x01;                          // Enable SPI3 Channel 0

        // enable the ADS7846 so it can generate a touch interrupt.
        // this consists of reading any channel, but setting the
        // power down mode in the control byte to 00b.  note we
        // flush the returned data
        //ads_rd(ADS7846E_S | ADS7846E_PD_ADC | ADS7846E_ADD_DFR_X);
        ads_rd(ADS7846E_S | ADS7846E_PD_ADC | ADS7846E_8BIT | ADS7846E_ADD_DFR_Y);
//      ads_rd(ADS7846E_S | ADS7846E_PD_ADC | ADS7846E_ADD_DFR_Y);
        temp = SPI3_REG(SPI_RXD0);

        return 0;
}

//--------------------------------------------------------------------------
int ads_rd(uchar ads_ctl)
{
        int timeout = 100;
        volatile uchar temp0, temp1;

        // the OMAP3530 only handles up to 16-bits per transfer
        // so we send 8-bits at a time to get our total of 24

//      SPI3_REG(SPI_TXD0) = ads_ctl;
//      udelay(10);
//      while (!(SPI3_REG(SPI_IRQSTATUS) & SPI_TX0_EMPTY));
//      while (!(SPI3_REG(SPI_IRQSTATUS) & SPI_RX0_FULL));
//      temp0 = SPI3_REG(SPI_RXD0);
//
//      SPI3_REG(SPI_TXD0) = 0;
//      udelay(10);
//      while (!(SPI3_REG(SPI_IRQSTATUS) & SPI_TX0_EMPTY));
//      while (!(SPI3_REG(SPI_IRQSTATUS) & SPI_RX0_FULL));
//      temp0 = SPI3_REG(SPI_RXD0);
//
//      SPI3_REG(SPI_TXD0) = 0;
//      udelay(10);
//      while (!(SPI3_REG(SPI_IRQSTATUS) & SPI_TX0_EMPTY));
//      while (!(SPI3_REG(SPI_IRQSTATUS) & SPI_RX0_FULL));
//      temp1 = SPI3_REG(SPI_RXD0);

        SPI3_REG(SPI_TXD0) = ads_ctl;
        udelay(10);
        while (!(SPI3_REG(SPI_CH0_STAT) & SPI_CH_TX0_EMPTY));
        while (!(SPI3_REG(SPI_CH0_STAT) & SPI_CH_RX0_FULL));
        temp0 = SPI3_REG(SPI_RXD0);

        SPI3_REG(SPI_TXD0) = 0;
        udelay(10);
        while (!(SPI3_REG(SPI_CH0_STAT) & SPI_CH_TX0_EMPTY));
        while (!(SPI3_REG(SPI_CH0_STAT) & SPI_CH_RX0_FULL));
        temp0 = SPI3_REG(SPI_RXD0);

//      SPI3_REG(SPI_TXD0) = 0;
//      udelay(10);
//      while (!(SPI3_REG(SPI_CH0_STAT) & SPI_CH_TX0_EMPTY));
//      while (!(SPI3_REG(SPI_CH0_STAT) & SPI_CH_RX0_FULL));
//      temp1 = SPI3_REG(SPI_RXD0);
        temp1 = 0;
        return ((temp0 << 8) | temp1);
}

//--------------------------------------------------------------------------
char *adsHelp[] = {
        "Screen touch demo using ADS7846 and OMAP3530 SPI port.",
        "",
        0
};

int ads(int argc, char *argv[])
{
        uchar c;
        int pen, i;
        int average_x, average_y;

        // init the SPI and ADS7846
        if (ads_init() == -1)
        {
                printf("Error intializing ADS7846!\n");
                return (CMD_FAILURE);
        }

        printf("Waiting for Touch (Press \'X\' to end test)...\n");

        pen = 0;
        while (1)
        {
                if (gotachar())
                {
                        c = getchar();
                        if ((c == 'X') || (c == 'x')) goto done;
                }
                if (GPIO_tst(PIRQ) == 0)
                {
                        printf("Pen Down....\n");
                        pen = 1;
                        while(GPIO_tst(PIRQ) == 0) // keep reading until touch goes away
                        {
                                average_x = 0;
                                average_y = 0;

                                // display every 256 samples (less if pen is down a short time)
                                for (i = 0; i < 256 ; i++)
                                {
//                                      average_x += ads_rd(ADS7846E_S | ADS7846E_PD_ADC | ADS7846E_ADD_DFR_X);
//                                      average_y += ads_rd(ADS7846E_S | ADS7846E_PD_ADC | ADS7846E_ADD_DFR_Y);
                                        average_x += ads_rd(ADS7846E_S | ADS7846E_PD_ADC | ADS7846E_8BIT | ADS7846E_ADD_DFR_X);
                                        average_y += ads_rd(ADS7846E_S | ADS7846E_PD_ADC | ADS7846E_8BIT | ADS7846E_ADD_DFR_Y);
                                }
                                printf("X = %04d, Y = %04d\n", average_x/i, average_y/i);

                        } // while pen is down
                }
                if (pen)
                {
                        printf("Pen Up....\n");
                        pen = 0;
                }

        }

done:           
        return(CMD_SUCCESS);
}