main.cpp

00001 #include "mbed.h"
00002 #include "USBKeyboard.h"
00003 
00004 #define LOG(args...)        // printf(args)
00005 
00006 #define THRESHOLD   2
00007 #define TOUCH_N     6
00008 
00009 BusOut leds(LED1, LED2, LED3, LED4);
00010 Ticker tick;
00011 USBKeyboard keyboard;
00012 
00013 uint8_t       key_map[TOUCH_N] = {RIGHT_ARROW, LEFT_ARROW, DOWN_ARROW, UP_ARROW, ' ', '\n'};
00014 PinName       touch_pin[TOUCH_N] = {A0, A1, A2, A3, A4, A5};
00015 DigitalInOut *p_touch_io[TOUCH_N];
00016 
00017 uint8_t touch_data[TOUCH_N] = {0, };
00018 
00019 void detect(void)
00020 {
00021     for (int i = 0; i < TOUCH_N; i++) {
00022         uint8_t count = 0;
00023         DigitalInOut *touch_io = p_touch_io[i];
00024         
00025         touch_io->input();
00026         touch_data[i] <<= 1;
00027         while (touch_io->read()) {
00028             count++;
00029             if (count > THRESHOLD) {
00030                 touch_data[i] |= 0x01;
00031                 break;
00032             }
00033         }
00034         touch_io->output();
00035         touch_io->write(1);
00036         
00037         if (0x01 == touch_data[i]) {            // a measurement is about the threshold, get a touch
00038             leds = 1 << i;
00039             keyboard.putc(key_map[i]);
00040             LOG("No %d key is touched\r\n", i);
00041         } else if (0x80 == touch_data[i]) {     // last 7 measurement is under the threshold, touch is released
00042             leds = 0x00;
00043             LOG("No %d key is released\r\n", i);
00044         }
00045     }
00046 }
00047 
00048 int main()
00049 {
00050     // setup
00051     for (int i = 0; i < TOUCH_N; i++) {
00052         p_touch_io[i] = new DigitalInOut(touch_pin[i]);
00053         p_touch_io[i]->mode(PullDown);
00054         p_touch_io[i]->output();
00055         p_touch_io[i]->write(1);
00056     }
00057     
00058     tick.attach(detect, 1.0 / 64.0);
00059     
00060     while(1) {
00061         // do something
00062         wait(1);
00063     }
00064 }