68 lines
2.0 KiB
C
68 lines
2.0 KiB
C
/*
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Capacitive touch sensor demo
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*/
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#include <avr/io.h>
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#include <util/delay.h>
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#include <avr/interrupt.h>
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#include <avr/power.h>
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#include "pinDefines.h"
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#include "USART.h"
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#define SENSE_TIME 50
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#define THRESHOLD 12000
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// ------- Global Variables ---------- //
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volatile uint16_t chargeCycleCount;
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// ------- Functions -------- //
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void initPinChangeInterrupt(void) {
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PCICR |= (1 << PCIE1); /* enable Pin-change interrupts 1 (bank C) */
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PCMSK1 |= (1 << PC1); /* enable specific interrupt for our pin PC1 */
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}
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ISR(PCINT1_vect) {
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chargeCycleCount++; /* count this change */
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CAP_SENSOR_DDR |= (1 << CAP_SENSOR); /* output mode */
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_delay_us(1); /* charging delay */
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CAP_SENSOR_DDR &= ~(1 << CAP_SENSOR); /* set as input */
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PCIFR |= (1 << PCIF1); /* clear the pin-change interrupt */
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}
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int main(void) {
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// -------- Inits --------- //
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clock_prescale_set(clock_div_1); /* full speed */
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initUSART();
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printString("==[ Cap Sensor ]==\r\n\r\n");
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LED_DDR = 0xff;
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MCUCR |= (1 << PUD); /* disable all pullups */
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CAP_SENSOR_PORT |= (1 << CAP_SENSOR); /* we can leave output high */
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initPinChangeInterrupt();
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// ------ Event loop ------ //
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while (1) {
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chargeCycleCount = 0; /* reset counter */
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CAP_SENSOR_DDR |= (1 << CAP_SENSOR); /* start with cap charged */
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sei(); /* start up interrupts, counting */
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_delay_ms(SENSE_TIME);
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cli(); /* done */
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if (chargeCycleCount < THRESHOLD) {
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LED_PORT = 0xff;
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}
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else {
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LED_PORT = 0;
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}
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printWord(chargeCycleCount); /* for fine tuning */
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printString("\r\n");
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} /* End event loop */
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return 0; /* This line is never reached */
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}
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