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intel_edison_fab_c.c: Fix edison disabled pwm stuck at high

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Edison pwm can stuck at high if pin is disabled during ON pwm peroid.
Workaround is to force zero duty time before disabling the pin.

Signed-off-by: Billy Bai <belugon@outlook.com>
Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>
This commit is contained in:
belugon
2016-10-04 08:17:00 +00:00
committed by Brendan Le Foll
parent c1017bb6ea
commit 2558866d4a
1 changed files with 13 additions and 1 deletions
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14
src/x86/intel_edison_fab_c.c
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@@ -30,6 +30,7 @@
#include <sys/ioctl.h>
#include <linux/spi/spidev.h>
#include <errno.h>
#include <time.h>
#include "common.h"
#include "x86/intel_edison_fab_c.h"
@@ -377,7 +378,18 @@ mraa_result_t
mraa_intel_edison_pwm_enable_pre(mraa_pwm_context dev, int enable) {
// PWM 0% duty workaround: update state array
// if someone first ran write(0) and then enable(1).
if ((pwm_disabled[dev->pin] == 1) && (enable == 1)) { pwm_disabled[dev->pin] = 0; }
if ((pwm_disabled[dev->pin] == 1) && (enable == 1)) {
pwm_disabled[dev->pin] = 0;
return MRAA_SUCCESS;
}
if (enable == 0) {
// Set duty cycle to 0 before disable pwm.
// Edison PWM output stuck at high if disabled during ON period
mraa_pwm_pulsewidth_us(dev, 0);
// Sleep 2 period to allow change take effect
usleep(dev->period / 500);
}
return MRAA_SUCCESS;
}