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////////////////////////////////////////////////////////////////////////////////

//

// Filename:    keypad.c

//

// Project:     CMod S6 System on a Chip, ZipCPU demonstration project

//

// Purpose:     A device driver (task) for the 16 character keypad.

//

// Creator:     Dan Gisselquist, Ph.D.

//              Gisselquist Technology, LLC

//

////////////////////////////////////////////////////////////////////////////////

//

// Copyright (C) 2015-2016, Gisselquist Technology, LLC

//

// This program is free software (firmware): you can redistribute it and/or

// modify it under the terms of  the GNU General Public License as published

// by the Free Software Foundation, either version 3 of the License, or (at

// your option) any later version.

//

// This program is distributed in the hope that it will be useful, but WITHOUT

// ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY or

// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

// for more details.

//

// You should have received a copy of the GNU General Public License along

// with this program.  (It's in the $(ROOT)/doc directory, run make with no

// target there if the PDF file isn't present.)  If not, see

// <http://www.gnu.org/licenses/> for a copy.

//

// License:     GPL, v3, as defined and found on www.gnu.org,

//              http://www.gnu.org/licenses/gpl.html

//

//

////////////////////////////////////////////////////////////////////////////////

//

//

#include "board.h"

#ifdef ZIPOS

#include "../zipos/ktraps.h"

#include "../zipos/kfildes.h"

#endif

static const int keymap[] = {

        0x01,0x02,0x03,0x0a,

        0x04,0x05,0x06,0x0b,

        0x07,0x08,0x09,0x0c,

        0x00,0x0f,0x0e,0x0d

};

int     keypadread(void) {

        int     row, col, key;

        IOSPACE *sys = (IOSPACE *)IOADDR;

        row = sys->io_spio & 0x0f00;

        if (row != 0x0f00) {

                // If a button is still pressed .. 

                //

                // Check columns one and two to see if they were responsible

                // for the button

                sys->io_spio = 0x0cf00;

                // Get the result

                col = sys->io_spio;

                if ((col&0x0f00)!=0x0f00) {

                        // Column one or two is pressed

                        sys->io_spio = 0x0ef00;

                        col = sys->io_spio;

                        if ((col&0x0f00)!=0x0f00)

                                col = 0;

                        else

                                col = 1;

                } else {

                        // Must be column three or four

                        sys->io_spio = 0x7f00;

                        col = sys->io_spio;

                        if ((col & 0x0f00)!= 0x0f00) // Column 4

                                col = 3;

                        else

                                col = 2;

                } sys->io_spio = 0x0f00; // Reset column pins to zero

                if (row == (int)(sys->io_spio & 0x0f00)) {

                        // The key didn't change, so we might have something

                        row >>= 8;

                        row &= 0x0f;

                        row ^= 0x0f;

                        // Found the pin

                        if (row == 1)

                                row=0;

                        else if (row == 2)

                                row = 1;

                        else if (row == 4)

                                row = 2;

                        else if (row == 8)

                                row = 3;

                        else

                                // Two or more buttons were pressed

                                // -- declare an error

                                row = -1;

                        if (row>=0) {

                                key = (row |(col<<2));

                                key = keymap[key];

                        } else key = -1;

                } else key = -1;

        } else key = -1;

        if (sys->io_pic & INT_ENABLE)

                sys->io_pic = INT_ENABLE|INT_KEYPAD;

        else sys->io_pic = INT_KEYPAD;

        return key;

}

void    keypad_wait_for_release(void) {

        IOSPACE *sys = (IOSPACE *)IOADDR;

        sys->io_spio = 0x0f00;

        while((sys->io_spio & 0x0f00)!=0x0f00)

#ifdef  ZIPOS

                wait(0,2);

#else

                ;

#endif

}

#ifdef ZIPOS

void keypad_task(void) {

        clear(INT_KEYPAD);

        while(1) {

                int     key;

                wait(INT_KEYPAD,-1); // Automatically clears

                key = keypadread();

                write(FILENO_STDOUT, &key, 1);

                // Prepare for the next key

                clear(INT_KEYPAD);

        }

}

#endif