Open_Access_Control_Ethernet/PCATTACH/PCATTACH.cpp

139 lines
3.1 KiB
C++

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