/elec/audio-switcher

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Viewing changes to src/VirtualSerial.c

  • Committer: Tim Marston
  • Date: 2012-11-23 00:00:34 UTC
  • Revision ID: tim@ed.am-20121123000034-386kbpshw5i7m8wi
added debouncing, button press detection and relay state toggling

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Lines of Context:
src/VirtualSerial.c
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        DDRB |= RELAY;
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}
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#define BUFFERLEN 10
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void loop()
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{
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        // debounce button (PD7)
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        static int saved_since = 0;
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        unsigned long now = millis();
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        unsigned long real_button_state = PIND & BUTTON;
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        bool button_state_changed = false;
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        if( saved_button_state != real_button_state ) {
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                saved_button_state = real_button_state;
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                saved_since = now;
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                         now - saved_since > 25 )
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        {
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                button_state = saved_button_state;
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                button_state_changed = true;
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        }
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        // read buffer from serial
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        static int buffer_pos = 0;
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        static char buffer[ BUFFERLEN ] = "";
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        int got = getc( &USBSerialStream );
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        bool got_command = false;
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        switch( got ) {
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        case EOF:
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        case 0: break;
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        case '\r': 
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        case '\n': got_command = true; break;
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        case ' ':
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        case '\t':
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                if( !buffer_pos ) break;
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                // fall through
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        default:
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                if( buffer_pos < ( BUFFERLEN - 1 ) )
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                        buffer[ buffer_pos++ ] = got;
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                buffer[ buffer_pos ] = 0;
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        }
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        }
 
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        // on rising edge of press, set toggle
 
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        static int last_button_state = 0;
 
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        bool toggle = false;
 
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        if( last_button_state != button_state )
 
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        {
 
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                last_button_state = button_state;
 
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                if( !button_state ) toggle = true;
 
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        }
 
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        // toggle the relay
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        static bool relay_state = false;
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        bool toggle_relay = false;
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        // handle command
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        if( got_command )
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        {
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                // command: turn relay off
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                if( !strcmp( buffer, "0" ) ) {
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                        if( relay_state ) toggle_relay = true;
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                }
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                // command: turn relay on
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                else if( !strcmp( buffer, "1" ) ) {
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                        if( !relay_state ) toggle_relay = true;
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                }
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                // command: report relay state
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                else if( !strcmp( buffer, "?" ) ) {
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                        fputs( relay_state? "1\r\n" : "0\r\n", &USBSerialStream );
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                }
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                // command: toggle relay state
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                else if( !strcmp( buffer, "." ) ) {
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                        toggle_relay = true;
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                }
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                // clear command
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                buffer_pos = buffer[ 0 ] = 0;
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        }
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        // handle button press?
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        if( button_state_changed && !button_state )
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        {
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                toggle_relay = true;
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        }
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        // toggle the relay?
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        if( toggle_relay )
 
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        if( toggle )
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        {
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                relay_state = !relay_state;
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        {
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                loop();
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                /* Must throw away unused bytes from the host, or it will lock up while
 
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                 * waiting for the device */
 
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                CDC_Device_ReceiveByte(&VirtualSerial_CDC_Interface);
 
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                CDC_Device_USBTask(&VirtualSerial_CDC_Interface);
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                USB_USBTask();
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        }
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        LEDs_Init();
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        USB_Init();
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        // my init
 
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        // do my init
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        init();
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        // set up arduino wiring.c