STM32W108CBU6 STMICROELECTRONICS [STMicroelectronics], STM32W108CBU6 Datasheet - Page 107

• Manufacturer Part Number: STM32W108CBU6
• Description: High-performance, IEEE 802.15.4 wireless system-on-chip
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

STM32W108CB, STM32W108HB
Note:
Using one timer to enable the other timer
In this example, the enable of Timer 2 is controlled with the output compare 1 of Timer 1.
Refer to
OC1REF of Timer 1 is high. Both counter clock frequencies are divided by 3 by the
prescaler compared to CK_INT (fCK_CNT = fCK_INT /3).
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The counter 2 clock is not synchronized with counter 1, this mode only affects the Timer 2
counter enable signal.
Figure 41. Gating timer 2 with OC1REF of timer 1
In the example in
being started. So they start counting from their current value. It is possible to start from a
given value by resetting both timers before starting Timer 1, then writing the desired value in
the timer counters. The timers can easily be reset by software using the TIM_UG bit in the
TIMx_EGR registers.
The next example, synchronizes Timer 1 and Timer 2. Timer 1 is the master and starts from
0. Timer 2 is the slave and starts from 0xE7. The prescaler ratio is the same for both timers.
Timer 2 stops when Timer 1 is disabled by writing 0 to the TIM_CEN bit in the TIM1_CR1
register:
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Configure Timer 1 in master mode to send its Output Compare Reference (OC1REF)
signal as trigger output (TIM_MMS = 100 in the TIM1_CR2 register).
Configure the Timer 1 OC1REF waveform (TIM1_CCMR1 register).
Configure Timer 2 to get the input trigger from Timer 1 (TIM_TS = 000 in the
TIM2_SMCR register).
Configure Timer 2 in gated mode (TIM_SMS = 101 in the TIM2_SMCR register).
Enable Timer 2 by writing 1 in the TIM_CEN bit (TIM2_CR1 register).
Start Timer 1 by writing 1 in the TIM_CEN bit (TIM1_CR1 register).
Configure Timer 1 in master mode to send its Output Compare Reference (OC1REF)
signal as trigger output (TIM_MMS = 100 in the TIM1_CR2 register).
Configure the Timer 1 OC1REF waveform (TIM1_CCMR1 register).
Configure Timer 2 to get the input trigger from Timer 1 (TIM_TS = 000 in the
TIM2_SMCR register).
Configure Timer 2 in gated mode (TIM_SMS = 101 in the TIM2_SMCR register).
Reset Timer 1 by writing 1 in the TIM_UG bit (TIM1_EGR register).
Reset Timer 2 by writing 1 in the TIM_UG bit (TIM2_EGR register).
Figure 40
Figure
for connections. Timer 2 counts on the divided internal clock only when
41, the Timer 2 counter and prescaler are not initialized before
Doc ID 16252 Rev 2
General-purpose timers
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