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[M487] Fix abnormal pulse on re-configuring pwmout 

The issue is met in ARM mbed CI test tests-api-pwm.
pull/4608/head
ccli8 2017-06-21 14:19:15 +08:00
parent 39a9f05491
commit 77ea786c04
1 changed files with 17 additions and 10 deletions
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27
targets/TARGET_NUVOTON/TARGET_M480/pwmout_api.c
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@ -57,7 +57,7 @@ static const struct nu_modinit_s pwm_modinit_tab[] = {
{NC, 0, 0, 0, 0, (IRQn_Type) 0, NULL}
};
static void pwmout_config(pwmout_t* obj);
static void pwmout_config(pwmout_t* obj, int start);
void pwmout_init(pwmout_t* obj, PinName pin)
{
@ -91,11 +91,7 @@ void pwmout_init(pwmout_t* obj, PinName pin)
// Default: period = 10 ms, pulse width = 0 ms
obj->period_us = 1000 * 10;
obj->pulsewidth_us = 0;
pwmout_config(obj);
// Enable output of the specified PWM channel
EPWM_EnableOutput(pwm_base, 1 << chn);
EPWM_Start(pwm_base, 1 << chn);
pwmout_config(obj, 0);
((struct nu_pwm_var *) modinit->var)->en_msk |= 1 << chn;
@ -128,7 +124,7 @@ void pwmout_free(pwmout_t* obj)
void pwmout_write(pwmout_t* obj, float value)
{
obj->pulsewidth_us = NU_CLAMP((uint32_t) (value * obj->period_us), 0, obj->period_us);
pwmout_config(obj);
pwmout_config(obj, 1);
}
float pwmout_read(pwmout_t* obj)
@ -153,7 +149,7 @@ void pwmout_period_us(pwmout_t* obj, int us)
uint32_t pulsewidth_us_old = obj->pulsewidth_us;
obj->period_us = us;
obj->pulsewidth_us = NU_CLAMP(obj->period_us * pulsewidth_us_old / period_us_old, 0, obj->period_us);
pwmout_config(obj);
pwmout_config(obj, 1);
}
void pwmout_pulsewidth(pwmout_t* obj, float seconds)
@ -169,7 +165,7 @@ void pwmout_pulsewidth_ms(pwmout_t* obj, int ms)
void pwmout_pulsewidth_us(pwmout_t* obj, int us)
{
obj->pulsewidth_us = NU_CLAMP(us, 0, obj->period_us);
pwmout_config(obj);
pwmout_config(obj, 1);
}
int pwmout_allow_powerdown(void)
@ -192,10 +188,15 @@ int pwmout_allow_powerdown(void)
return 1;
}
static void pwmout_config(pwmout_t* obj)
static void pwmout_config(pwmout_t* obj, int start)
{
EPWM_T *pwm_base = (EPWM_T *) NU_MODBASE(obj->pwm);
uint32_t chn = NU_MODSUBINDEX(obj->pwm);
// To avoid abnormal pulse on (re-)configuration, follow the sequence: stop/configure(/re-start).
// NOTE: The issue is met in ARM mbed CI test tests-api-pwm on M487.
EPWM_ForceStop(pwm_base, 1 << chn);
// NOTE: Support period < 1s
// NOTE: ARM mbed CI test fails due to first PWM pulse error. Workaround by:
// 1. Inverse duty cycle (100 - duty)
@ -203,6 +204,12 @@ static void pwmout_config(pwmout_t* obj)
// This trick is here to pass ARM mbed CI test. First PWM pulse error still remains.
EPWM_ConfigOutputChannel2(pwm_base, chn, 1000 * 1000, 100 - obj->pulsewidth_us * 100 / obj->period_us, obj->period_us);
pwm_base->POLCTL |= 1 << (EPWM_POLCTL_PINV0_Pos + chn);
if (start) {
// Enable output of the specified PWM channel
EPWM_EnableOutput(pwm_base, 1 << chn);
EPWM_Start(pwm_base, 1 << chn);
}
}
#endif