STM8S datasheet(225/467 Pages) STMICROELECTRONICS

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RM0016

16-bit general purpose timers (TIM2, TIM3, TIM5)

261

For more details refer to Section 17.3: TIM1 time base unit on page 141.

Prescaler

The prescaler implementation is as follows:

•

The prescaler is based on a 16-bit counter controlled through a 4-bit register (in the

TIMx_PSCR register). It can be changed on the fly as this control register is buffered. It

can divide the counter clock frequency by any power of 2 from 1 to 32768.

The counter clock frequency is calculated as follows:

fCK_CNT = fCK_PSC/2(PSCR[3:0])

The prescaler value is loaded through a preload register. The shadow register, which

contains the current value to be used is loaded as soon as the LS Byte has been written.

The new prescaler value is taken into account in the following period (after the next counter

update event).

Read operations to the TIMx_PSCR registers access the preload registers, so no special

care needs to be taken to read them.

Counter operation

Refer to Section 17.3.4: Up-counting mode on page 143.

18.4.2

Clock/trigger controller

A clock/trigger controller and the associated TIMx_CR2 and TIMx_SMCR registers are not

implemented in TIM2/TIM3, only in TIM5. Refer to Section 17.4: TIM1 clock/trigger

controller on page 151

STM8S Datasheet(PDF) 225 Page - STMicroelectronics