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RC: disable interrupts when reading the RC registers 

this prevents getting bogus values which could cause a flight mode
change
This commit is contained in:
Andrew Tridgell 2012-03-04 20:34:24 +11:00
parent efe2686b33
commit 2969e16f7d
2 changed files with 28 additions and 27 deletions
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14
libraries/APM_RC/APM_RC_APM1.cpp
View File

@ -199,18 +199,18 @@ uint16_t APM_RC_APM1::InputCh(uint8_t ch)
return _HIL_override[ch];
}
// Because servo pulse variables are 16 bits and the interrupts are running values could be corrupted.
// We dont want to stop interrupts to read radio channels so we have to do two readings to be sure that the value is correct...
// we need to stop interrupts to be sure we get a correct 16 bit value
cli();
result = _PWM_RAW[ch];
if (result != _PWM_RAW[ch]) {
result = _PWM_RAW[ch]; // if the results are different we make a third reading (this should be fine)
}
result >>= 1; // Because timer runs at 0.5us we need to do value/2
sei();
// Because timer runs at 0.5us we need to do value/2
result >>= 1;
// Limit values to a valid range
result = constrain(result,MIN_PULSEWIDTH,MAX_PULSEWIDTH);
_radio_status = 0; // Radio channel read
return(result);
return result;
}
uint8_t APM_RC_APM1::GetState(void)

17
libraries/APM_RC/APM_RC_APM2.cpp
View File

@ -20,6 +20,7 @@
*/
#include "APM_RC_APM2.h"
#include <avr/interrupt.h>
#if defined(ARDUINO) && ARDUINO >= 100
#include "Arduino.h"
#else
@ -195,23 +196,23 @@ void APM_RC_APM2::disable_out(uint8_t ch)
uint16_t APM_RC_APM2::InputCh(unsigned char ch)
{
uint16_t result;
uint16_t result2;
if (_HIL_override[ch] != 0) {
return _HIL_override[ch];
}
// Because servo pulse variables are 16 bits and the interrupts are running values could be corrupted.
// We dont want to stop interrupts to read radio channels so we have to do two readings to be sure that the value is correct...
result = _PWM_RAW[ch]>>1; // Because timer runs at 0.5us we need to do value/2
result2 = _PWM_RAW[ch]>>1;
if (result != result2)
result = _PWM_RAW[ch]>>1; // if the results are different we make a third reading (this should be fine)
// we need to block interrupts during the read of a 16 bit
// value
cli();
result = _PWM_RAW[ch];
sei();
// Because timer runs at 0.5us we need to do value/2
result >>= 1;
// Limit values to a valid range
result = constrain(result,MIN_PULSEWIDTH,MAX_PULSEWIDTH);
_radio_status = 0; // Radio channel read
return(result);
return result;
}
unsigned char APM_RC_APM2::GetState(void)