139 lines
3.1 KiB
C++
139 lines
3.1 KiB
C++
#include "pins_arduino.h"
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#include "PCATTACH.h"
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/*
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* an extension to the interrupt support for arduino.
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* add pin change interrupts to the external interrupts, giving a way
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* for users to have interrupts drive off of any pin.
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* Refer to avr-gcc header files, arduino source and atmega datasheet.
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*/
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/*
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* Theory: all IO pins on Atmega168 are covered by Pin Change Interrupts.
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* The PCINT corresponding to the pin must be enabled and masked, and
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* an ISR routine provided. Since PCINTs are per port, not per pin, the ISR
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* must use some logic to actually implement a per-pin interrupt service.
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*/
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PCATTACH::PCATTACH(){
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}
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PCATTACH::~PCATTACH(){
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}
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PCATTACH pc1;
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/* Pin to interrupt map:
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* D0-D7 = PCINT 16-23 = PCIR2 = PD = PCIE2 = pcmsk2
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* D8-D13 = PCINT 0-5 = PCIR0 = PB = PCIE0 = pcmsk0
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* A0-A5 (D14-D19) = PCINT 8-13 = PCIR1 = PC = PCIE1 = pcmsk1
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*/
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volatile uint8_t *port_to_pcmask[] = {
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&PCMSK0,
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&PCMSK1,
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&PCMSK2
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};
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typedef void (*voidFuncPtr)(void);
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volatile static voidFuncPtr PCintFunc[24] = {
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NULL };
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volatile static uint8_t PCintLast[3];
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/*
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* attach an interrupt to a specific pin using pin change interrupts.
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* First version only supports CHANGE mode.
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*/
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void PCATTACH::PCattachInterrupt(uint8_t pin, void (*userFunc)(void), int mode) {
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uint8_t bit = digitalPinToBitMask(pin);
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uint8_t port = digitalPinToPort(pin);
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uint8_t slot;
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volatile uint8_t *pcmask;
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if (mode != CHANGE) {
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return;
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}
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// map pin to PCIR register
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if (port == NOT_A_PORT) {
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return;
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}
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else {
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port -= 2;
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pcmask = port_to_pcmask[port];
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}
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slot = port * 8 + (pin % 8);
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PCintFunc[slot] = userFunc;
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// set the mask
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*pcmask |= bit;
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// enable the interrupt
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PCICR |= 0x01 << port;
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}
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void PCATTACH::PCdetachInterrupt(uint8_t pin) {
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uint8_t bit = digitalPinToBitMask(pin);
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uint8_t port = digitalPinToPort(pin);
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volatile uint8_t *pcmask;
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// map pin to PCIR register
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if (port == NOT_A_PORT) {
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return;
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}
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else {
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port -= 2;
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pcmask = port_to_pcmask[port];
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}
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// disable the mask.
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*pcmask &= ~bit;
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// if that's the last one, disable the interrupt.
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if (*pcmask == 0) {
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PCICR &= ~(0x01 << port);
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}
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}
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// common code for isr handler. "port" is the PCINT number.
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// there isn't really a good way to back-map ports and masks to pins.
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void PCATTACH::PCint(uint8_t port) {
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uint8_t bit;
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uint8_t curr;
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uint8_t mask;
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uint8_t pin;
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// get the pin states for the indicated port.
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curr = *portInputRegister(port+2);
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mask = curr ^ PCintLast[port];
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PCintLast[port] = curr;
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// mask is pins that have changed. screen out non pcint pins.
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if ((mask &= *port_to_pcmask[port]) == 0) {
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return;
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}
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// mask is pcint pins that have changed.
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for (uint8_t i=0; i < 8; i++) {
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bit = 0x01 << i;
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if (bit & mask) {
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pin = port * 8 + i;
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if (PCintFunc[pin] != NULL) {
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PCintFunc[pin]();
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}
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}
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}
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}
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SIGNAL (PCINT0_vect) {
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pc1.PCint(0);
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}
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SIGNAL (PCINT1_vect) {
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pc1.PCint(1);
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}
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SIGNAL (PCINT2_vect) {
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pc1.PCint(2);
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}
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