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stm32: timer: Clarify some misleading comments.

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Start clearing up misleading/redundant commentary.
This commit is contained in:
Valentin Ochs
2016-10-18 11:32:34 +02:00
committed by Karl Palsson
parent 1260b16772
commit da04ccdf71
2 changed files with 7 additions and 7 deletions
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2
examples/stm32/f1/stm32-h103/timer/timer.c
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@@ -90,7 +90,7 @@ static void tim_setup(void)
/* Reset prescaler value. */ /* Reset prescaler value. */
timer_set_prescaler(TIM2, 36000); timer_set_prescaler(TIM2, 36000);
/* Enable preload. */ /* Disable preload. */
timer_disable_preload(TIM2); timer_disable_preload(TIM2);
/* Continous mode. */ /* Continous mode. */

12
examples/stm32/f4/stm32f4-discovery/timer/timer.c
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@@ -92,7 +92,7 @@ static void tim_setup(void)
TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP); TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP);
/* Reset prescaler value. /* Reset prescaler value.
* Running the clock at 5kHz. * Running the clock at 10kHz.
*/ */
/* /*
* On STM32F4 the timers are not running directly from pure APB1 or * On STM32F4 the timers are not running directly from pure APB1 or
@@ -104,17 +104,17 @@ static void tim_setup(void)
* the APBx prescaler is set to 1 the derived timer APBx will equal the * the APBx prescaler is set to 1 the derived timer APBx will equal the
* original APBx frequencies. * original APBx frequencies.
* *
* In our case here the APB1 is devided by 4 system frequency and APB2 * In our case here the APB1 is system frequency divided by 4 and APB2
* divided by 2. This means APB1 timer will be 2 x APB1 and APB2 will * is system frequency divided by 2. This means APB1 timer will be 2 x
* be 2 x APB2. So when we try to calculate the prescaler value we have * APB1 and APB2 will be 2 x APB2. So when we try to calculate the
* to use rcc_apb1_freqency * 2!!! * prescaler value we have to use rcc_apb1_freqency * 2!!!
* *
* For additional information see reference manual for the stm32f4 * For additional information see reference manual for the stm32f4
* familiy of chips. Page 204 and 213 * familiy of chips. Page 204 and 213
*/ */
timer_set_prescaler(TIM2, ((rcc_apb1_frequency * 2) / 10000)); timer_set_prescaler(TIM2, ((rcc_apb1_frequency * 2) / 10000));
/* Enable preload. */ /* Disable preload. */
timer_disable_preload(TIM2); timer_disable_preload(TIM2);
/* Continous mode. */ /* Continous mode. */