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Fix two bugs of tiva pwm lower-half driver impl.

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This commit is contained in:
Young 2016-08-10 13:25:43 +08:00
parent 4838528266
commit e30a3b780c
1 changed files with 11 additions and 2 deletions
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13
arch/arm/src/tiva/tiva_pwm.c
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@ -374,9 +374,15 @@ static int tiva_pwm_start(FAR struct pwm_lowerhalf_s *dev,
tiva_pwm_putreg(chan, TIVA_PWMn_LOAD_OFFSET, load - 1); tiva_pwm_putreg(chan, TIVA_PWMn_LOAD_OFFSET, load - 1);
/* Configure PWM duty (refer to TM4C1294NC 23.4.8-9) */ /* Configure PWM duty (refer to TM4C1294NC 23.4.8-9)
*
* Workaround:
* When comp equals to load, the signal is never pulled down,
* so let comp equals to (comp-1)
*/
uint32_t comp = (uint32_t)((1 - (float)duty / g_pwm_counter) * load); uint32_t comp = (uint32_t)((1 - (float)duty / g_pwm_counter) * load);
comp = (duty == 0) ? (comp - 1) : (comp);
pwminfo("channel %d: comp = %u (%08x)\n", chan->channel_id, comp, comp); pwminfo("channel %d: comp = %u (%08x)\n", chan->channel_id, comp, comp);
if (chan->channel_id % 2 == 0) if (chan->channel_id % 2 == 0)
@ -394,7 +400,10 @@ static int tiva_pwm_start(FAR struct pwm_lowerhalf_s *dev,
/* Enable PWM channel (refer to TM4C1294NC 23.4.11) */ /* Enable PWM channel (refer to TM4C1294NC 23.4.11) */
putreg32((1 << chan->channel_id), chan->controller_base + TIVA_PWM_ENABLE_OFFSET); uint32_t enable = getreg32(chan->controller_base + TIVA_PWM_ENABLE_OFFSET);
enable |= (1 << chan->channel_id);
putreg32(enable, chan->controller_base + TIVA_PWM_ENABLE_OFFSET);
return OK; return OK;
} }