Encoder Mode and also get the counts (rising edge) from each input.

[clonephone82]

Dose someone know if it is possible to use TM3 in Encoder Mode. And also get the internal detected counts for each input. I use TIM3 channel 1 and 2 for the encoder.

many thanks

[waclawek.jan]

There is one more option, more of a trick - count one input as I've outlined above, through the TRGO-TRGI timers link, and use the other to trigger dummy DMA transfers, then NDTR of the DMA is your counter.

JW

[waclawek.jan]

> i got DOUBLED counts

The original STM32 timer supports only x4 and x2 modes (newer STM32 such as 'G4 supports also x1).

Simply divide what you read out from TIMx_CNT by two.

JW

[J__THAKKAR]

but where i am learning these they said to do these task without dividing it and if you know where it is exactly written about how many times it mutiplied then please mention it...

 

[waclawek.jan]

It is not *multiplied*. The x2 mode just means, that for every cycle (which contains 1 pulse = 2 edges on signal A and 1 pulse = 2 edges on signal B) the counter counts +-2 (because it counts both the rising and falling edge of one of the signals). The x4 mode counts both edges on both signals, so that is +-4 per cycle.

"Polarity selection" in Encoder mode is a bit misleading name (but is in fact good name for the main purpose of the timer channels set as input, i.e. Input Capture); in encoder mode this does not *select* the edge, but determines, whether the input signal is inverted or not, before it enters the decoder.

> where i am learning these they said to do these task without dividing it

You can't.

Your teacher maybe wants you to set the prescaler (TIMx_PSC) to perform that division, but I recommend not to do that (or you can do that just to fulfull a school assignment, but don't use it for real application).

JW