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/******************************************************************************
* The MIT License
*
* Copyright (c) 2010 Perry Hung.
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use, copy,
* modify, merge, publish, distribute, sublicense, and/or sell copies
* of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*****************************************************************************/
/**
* @file exti.c
* @brief External interrupt control routines
*/
#include "exti.h"
#include "libmaple.h"
#include "nvic.h"
#include "bitband.h"
static inline void dispatch_single_exti(uint32 exti_num);
static inline void dispatch_extis(uint32 start, uint32 stop);
/*
* Internal state
*/
typedef struct exti_channel {
void (*handler)(void);
uint32 irq_line;
} exti_channel;
static exti_channel exti_channels[] = {
{ .handler = NULL, .irq_line = NVIC_EXTI0 }, // EXTI0
{ .handler = NULL, .irq_line = NVIC_EXTI1 }, // EXTI1
{ .handler = NULL, .irq_line = NVIC_EXTI2 }, // EXTI2
{ .handler = NULL, .irq_line = NVIC_EXTI3 }, // EXTI3
{ .handler = NULL, .irq_line = NVIC_EXTI4 }, // EXTI4
{ .handler = NULL, .irq_line = NVIC_EXTI_9_5 }, // EXTI5
{ .handler = NULL, .irq_line = NVIC_EXTI_9_5 }, // EXTI6
{ .handler = NULL, .irq_line = NVIC_EXTI_9_5 }, // EXTI7
{ .handler = NULL, .irq_line = NVIC_EXTI_9_5 }, // EXTI8
{ .handler = NULL, .irq_line = NVIC_EXTI_9_5 }, // EXTI9
{ .handler = NULL, .irq_line = NVIC_EXTI_15_10 }, // EXTI10
{ .handler = NULL, .irq_line = NVIC_EXTI_15_10 }, // EXTI11
{ .handler = NULL, .irq_line = NVIC_EXTI_15_10 }, // EXTI12
{ .handler = NULL, .irq_line = NVIC_EXTI_15_10 }, // EXTI13
{ .handler = NULL, .irq_line = NVIC_EXTI_15_10 }, // EXTI14
{ .handler = NULL, .irq_line = NVIC_EXTI_15_10 }, // EXTI15
};
/*
* Convenience routines
*/
/**
* @brief Register a handler to run upon external interrupt.
*
* This function assumes that the interrupt request corresponding to
* the given external interrupt is masked.
*
* @param num External interrupt line number.
* @param port Port to use as source input for external interrupt.
* @param handler Function handler to execute when interrupt is triggered.
* @param mode Type of transition to trigger on, one of:
* EXTI_RISING, EXTI_FALLING, EXTI_RISING_FALLING.
* @see exti_num
* @see exti_port
* @see exti_trigger_mode
*/
void exti_attach_interrupt(afio_exti_num num,
afio_exti_port port,
voidFuncPtr handler,
exti_trigger_mode mode) {
ASSERT(handler);
/* Register the handler */
exti_channels[num].handler = handler;
/* Set trigger mode */
switch (mode) {
case EXTI_RISING:
bb_peri_set_bit(&EXTI_BASE->RTSR, num, 1);
break;
case EXTI_FALLING:
bb_peri_set_bit(&EXTI_BASE->FTSR, num, 1);
break;
case EXTI_RISING_FALLING:
bb_peri_set_bit(&EXTI_BASE->RTSR, num, 1);
bb_peri_set_bit(&EXTI_BASE->FTSR, num, 1);
break;
}
/* Map num to port */
afio_exti_select(num, port);
/* Unmask external interrupt request */
bb_peri_set_bit(&EXTI_BASE->IMR, num, 1);
/* Enable the interrupt line */
nvic_irq_enable(exti_channels[num].irq_line);
}
/**
* @brief Unregister an external interrupt handler
* @param num Number of the external interrupt line to disable.
* @see exti_num
*/
void exti_detach_interrupt(afio_exti_num num) {
/* First, mask the interrupt request */
bb_peri_set_bit(&EXTI_BASE->IMR, num, 0);
/* Then, clear the trigger selection registers */
bb_peri_set_bit(&EXTI_BASE->FTSR, num, 0);
bb_peri_set_bit(&EXTI_BASE->RTSR, num, 0);
/* Finally, unregister the user's handler */
exti_channels[num].handler = NULL;
}
/*
* Interrupt handlers
*/
void __irq_exti0(void) {
dispatch_single_exti(AFIO_EXTI_0);
}
void __irq_exti1(void) {
dispatch_single_exti(AFIO_EXTI_1);
}
void __irq_exti2(void) {
dispatch_single_exti(AFIO_EXTI_2);
}
void __irq_exti3(void) {
dispatch_single_exti(AFIO_EXTI_3);
}
void __irq_exti4(void) {
dispatch_single_exti(AFIO_EXTI_4);
}
void __irq_exti9_5(void) {
dispatch_extis(5, 9);
}
void __irq_exti15_10(void) {
dispatch_extis(10, 15);
}
/*
* Auxiliary functions
*/
/* Clear the pending bits for EXTIs whose bits are set in exti_msk.
*
* If a pending bit is cleared as the last instruction in an ISR, it
* won't actually be cleared in time and the ISR will fire again. To
* compensate, this function NOPs for 2 cycles after clearing the
* pending bits to ensure it takes effect. */
static inline void clear_pending_msk(uint32 exti_msk) {
EXTI_BASE->PR = exti_msk;
asm volatile("nop");
asm volatile("nop");
}
/* This dispatch routine is for non-multiplexed EXTI lines only; i.e.,
* it doesn't check EXTI_PR. */
static inline void dispatch_single_exti(uint32 exti) {
voidFuncPtr handler = exti_channels[exti].handler;
if (!handler) {
return;
}
handler();
clear_pending_msk(BIT(exti));
}
/* Dispatch routine for EXTIs which share an IRQ. */
static inline void dispatch_extis(uint32 start, uint32 stop) {
uint32 pr = EXTI_BASE->PR;
uint32 handled_msk = 0;
uint32 exti;
/* Dispatch user handlers for pending EXTIs. */
for (exti = start; exti <= stop; exti++) {
uint32 eb = BIT(exti);
if (pr & eb) {
voidFuncPtr handler = exti_channels[exti].handler;
if (handler) {
handler();
handled_msk |= eb;
}
}
}
/* Clear the pending bits for handled EXTIs. */
clear_pending_msk(handled_msk);
}
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