Timer with external clock in gated mode

[smrtkai]

Posted on April 11, 2016 at 09:39

Hi,

I would like to configure a timer as a slave in gated mode which has an external clock from another timer. So in my setup I do would have three timers. A ''clock timer'' which outputs a given clock frequency, a master timer which gates a slave timer.

In STM32CubeMX you can select a ''Clock Source'' to be an external pin (''ETR2''). In AN4013 describes the clock source as follows: ''The external clock mode2 uses the ETR pin as timer input clock.''

So I could output the clock signal on a pin from one timer and connect it as an external trigger for another timer. But I do not know which pin are the ETR pins.

So my question is: Which are the ETR pins for timers?

And: Is there maybe an easier solution? Without any hardware connection.

[Amel NASRI]

Posted on April 11, 2016 at 12:50

Hi smrtkai,

In the STM32Cube package, you find some examples that may help you to synchronize times, and so connect them internally.

I recommend you to refer to the example: STM32Cube_FW_F4_V1.11.0\Projects\STM324xG_EVAL\Examples\TIM\TIM_Synchronization.

Used device isn't precised, I provided the STM32F4 example. But you should find a similar example in other parts.

You have to refer to relevant reference manual depending on the product you are using to get more details about the timers synchronization feature.

If you still need to use the ETR pin, you have to refer to the datasheet of your product to know it.

-Mayla-

[Tesla DeLorean]

Posted on April 11, 2016 at 14:33

The Data Manual with list the ETR pins, some share channel functionality, search on ''_ETR''

The Reference Manual should have tables which provide ITR timer sources, on a per timer basis, for the internal connectivity.