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Merge branch 'lacklustrlabs-new_pulseIn'

This commit is contained in:
Roger Clark 2017-12-03 10:45:39 +11:00
parent a4ae0ce1f9 628dc25d7b
commit a5f9f905ad
1 changed files with 10 additions and 9 deletions
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19
STM32F1/cores/maple/stm32f1/wiring_pulse_f1.cpp
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@ -1,5 +1,6 @@
#include <wiring_pulse.h>
#include "boards.h"
#include "variant.h"
/* Measures the length (in microseconds) of a pulse on the pin; state is HIGH
* or LOW, the type of pulse to measure. Works on pulses from 2-3 microseconds
* to 3 minutes in length, but must be called at least a few dozen microseconds
@ -28,13 +29,13 @@
*/
uint32_t pulseIn( uint32_t pin, uint32_t state, uint32_t timeout )
{
// cache the port and bit of the pin in order to speed up the
// cache the IDR address and bit of the pin in order to speed up the
// pulse width measuring loop and achieve finer resolution. calling
// digitalRead() instead yields much coarser resolution.
gpio_dev *dev=PIN_MAP[pin].gpio_device;
uint32_t bit = (1U << PIN_MAP[pin].gpio_bit);
__io uint32_t * const idr = portInputRegister(digitalPinToPort(pin));
const uint32_t bit = digitalPinToBitMask(pin);
const uint32_t stateMask = (state ? bit:0);
uint32_t width = 0; // keep initialization out of time critical area
@ -45,23 +46,23 @@ uint32_t pulseIn( uint32_t pin, uint32_t state, uint32_t timeout )
volatile uint32_t dummyWidth=0;
// wait for any previous pulse to end
while ( (dev->regs->IDR & bit) == bit) {
while ((*idr & bit) == stateMask) {
if (numloops++ == maxloops) {
return 0;
}
dummyWidth++;
dummyWidth++;
}
// wait for the pulse to start
while ((dev->regs->IDR & bit) != bit) {
while ((*idr & bit) != stateMask) {
if (numloops++ == maxloops) {
return 0;
}
dummyWidth++;
dummyWidth++;
}
// wait for the pulse to stop
while ((dev->regs->IDR & bit) == bit) {
while ((*idr & bit) == stateMask) {
if (numloops++ == maxloops) {
return 0;
}